Thank you, Ken. And to add to your comment, we should note that billings growth, product revenue growth and total revenue growth were each at five-year highs.
Okay, let's start the more detailed Q1 discussion with revenue. Total revenue of $710 million was up 23% driven by industry-leading product revenue growth of 25%. Auto-driven growth was broad-based across geographies, Security Fabric products and use cases illustrating the market acceptance of our integrated, single platform, security strategy. Customer demand for security across their entire infrastructure and the diversity of our customer base. Product revenue growth was over 30% for both infrastructure and cloud fabric products. And all three geographic regions increased 20% or more. Demand for security fabric products was strong across all form factors, hardware, software, and virtual machines. The growth we experienced for product revenue was not the result of a few large deals, lower backlog or higher channel partner inventory levels. The product revenue growth also enables increases in services billings and future services revenue. In the first quarter service revenue of $470 million was up 22%. Support and related services revenue increased 23%, to $214 million. Security subscription services revenue increased 21% to $255 million benefiting from outsized growth from our cloud provider and SaaS security offerings.
Moving to the mix of FortiGate and Non-FortiGate platform revenue, the FortiGate segment of the Fabric platform saw revenue increase 17% driven by demand for entry-level and high-end FortiGate products. High-end includes 10 new NP7 powered FortiGates that were introduced in the past week, which includes today's announcement of the 71.21F. These new products now represent approximately 20% of high-end FortiGate shipments.
Our AC driven FortiGates give customers five to ten times more computing power than firewalls that run on common CPUs. The advanced computing power creates not only speed, but also the capacity to continue to add functionality to our operating system, driving our price for performance advantage. The Non-FortiGate segment saw revenue grow over 40% and now accounts for 31% of total revenue up four percentage points. The integrated security fabric solutions, consists of a complete range of form factors and delivery methods, including physical and virtual appliances, cloud, SaaS and professional software, as well as hosted and non-hosted solutions. Together, they provide a range of security solutions and form factors enabling integrated protection for hybrid environments and the expanding digital attack surface from the data center, to the endpoint, to the cloud.
Given the strong first quarter performance – revenue performance, we believe our Non-FortiGate platform is now on a pace to be a $1 billion business this year, representing an acceleration of this milestone.
Let's turn to revenue by geographies.
As summarized on Slide 5, revenue in the Asia Pacific area increased 26%; EMEA revenue increased 25%; and Americas posted revenue growth of 20%.
As I mentioned earlier, all three regions experienced product revenue growth of 20% or more.
Moving to billings.
The first quarter billings were $851 million, up 27%. We saw strong growth in both the FortiGate and non-FortiGate segments at a Security Fabric platform. The FortiGate segment delivered billings growth of 20%, accounting for 70% of total billings.
As shown on Slide 6, entry-level FortiGate posted very strong billings growth in the quarter. The non-FortiGate segment accounted for 30% of total billings and delivered billings growth of 50%, driving a four-point year-over-year mix shift to non-FortiGate. Taking together, these data points highlight the market acceptance of our single integrated security platform strategy.
In terms of billing growth by geos, APAC outperformed all geos followed by Europe, and the Americas. In the Americas, Canada had a very strong quarter and Latin America rebounded from the pandemic induced slowdown posted billings growth in the mid 20% range.
Moving to billings by customer segments, the small enterprise segment posted solid growth across all geos. This segment is driven by new customer acquisitions, customer Security Fabric expansions, solid execution by our channel partners and the large diverse makeup of this international customer segment. At the same time, we saw strong growth in our larger deals. The number of deals of $1 million, increased 74% to 66 deals in the first quarter. The pipeline for deals of a $1 million looks good for the remainder of the year.
As Ken noted, secure SD-WAN billings were 14% of total billings. SD-WAN as a key functionality and an integrated staffing solution.
Moving to worldwide billings by industry verticals was another strong international performance. The worldwide government sector topped all verticals at 19% of total billings and was up 60%. Service providers and MSSPs accounted for 16% of total billings. The rebound for education accelerated. We've done this growth of 50%. Retail turned into a solid quarter with billing growth of 21%.
Our strong and consistent billings and revenue performance over the past several years is testament to our geographic and customer diversity. The growing success with a single integrated security platform strategy and our ASIC advantage, which enables a shared operating system across the Security Fabric platform drives our price or performance advantage, increase the capacity to add features and functions while maintaining price points.
Moving back to the income statement.
As shown on Slide 4, total gross margin improved 10 basis points to 78.9%. Product gross margin improved 120 basis points to 62.6% benefiting from lower direct product cost. The increase in product gross margin offsets the drag on total gross margins from the revenue mix shift driven by the strong product revenue growth and a gross margin – and the gross margin FX headwind [indiscernible] about 25 basis points. Operating margin for the first quarter increased 210 basis points to 24.5%, benefitting from the strong revenue performance in the quarter. The benefit from lower travel and marketing program expenses are approximately 100 basis points. It was more than offset by an operating margin headwind from foreign exchange of about 150 basis points. To end the quarter – we end the quarter with total head count of 8,615, an increase of 16%.
Moving to the statement of cash flow summarized on Slide 7 and 8. Free cash flow for the first quarter came in at $264 million, up $22 million from the first quarter of 2020, despite a $24.5 million year-over-year increase in CapEx spending. We ended the year with total cash and investments of $3.1 billion, an increase of $1.5 billion. The increase includes the proceeds from our $1 billion investment grade debt issuance during the first quarter. The issuance followed our inaugural strong triple B credit ratings. Throughout the pandemic, we have leveraged the strength of our balance sheet as a competitive advantage to support our partners and customers as they experienced geo-specific economic challenges.
As a result daily sales outstanding increased seven days to 81 days and in line with our expectations and reflecting our earlier decisions to provide geographically targeted extended payment terms. Compared to the fourth quarter of 2020, DSI was on the first quarter of 2021 decreased six days, as we saw early progress towards returning to pre-pandemic payment terms. Inventory turns declined to 2.1 times from 2.5 times, reflecting the efforts we took to mitigate supply chain risk, including increasing our inventory levels, starting earlier in 2020.
We expect extended payment terms and higher inventory balances to be in effect as we move through 2021. Capital expenditures for the first quarter were $52 million, including $38 million related to construction and other real estate activity.
We expect to begin moving employees and the new Sunnyvale campus building in the middle of the year.
Although the timing will depend on local pandemic protocols and employee safety considerations. We estimate capital expenditures for second quarter between $30 million and $40 million for all of 2021 to between 150 and 179. The average contract term in the first quarter was approximately 27 months, up less than two months from the first quarter of 2020, and down approximately one month from the fourth quarter of 2020. Secure SD-WAN accounted for 15 deals of $1 million versus four in the first quarter of 2020, and contributed to the increase in average contract term.
As we look forward, our goal remains to balance growth and profitability. And given the growth opportunities we highlighted during the March Analyst Day and as confirmed in our first quarter results, we have tilted our bias towards growth for at least the next several quarters. The opportunities we see are supported by a strong pipeline, increased sales capacity and our development efforts, which include the NP7 chip and our new FortiOS7.0 operating system that was recently released.
Now I'd like to review our outlook for the second quarter guidance summarized on Slide 9, which is subject to disclaimers regarding forward-looking information that Peter provided at the beginning of the call.
For the second quarter, we expect billings in the range of $860 to $880 million. Revenue in the range of $733 million to $747 million. Non-GAAP gross margins of 78.5% to 79.5%. Non-GAAP operating margin of 24.5% to 25.5%, which includes an expected 100 basis points to 150 basis points headwind in foreign exchange. Non-GAAP earnings per share of $0.83 to $0.88, which assumes a share count of between $168 million and $170 million.
We expect a non-GAAP tax rate of 21%.
Before raising our 2021 guidance, I’d like to congratulate every member of the Fortinet team for the truly outstanding start to 2021.
For the 2021 we expect billings in the range of $3.685 billion to $3.745 billion, which at the mid point represents growth of approximately 20%. Revenue in the range of $3.080 billion to $3.130 billion, which at the mid point represents growth of approximately 20%. Total service revenue in the range of $2.020 billion to $2.050 billion, which represents growth of approximately 21% and implies product revenue growth of approximately 17%. Non-GAAP gross margin of 78% to 80%. Non-GAAP operating margin of 25% to 27%. When backing out the 2020 T&E benefit, the midpoint of the guidance represents a 50 to 100 basis point increase in 2021 operating margin, despite an expected headwind from foreign exchange. Non-GAAP earnings per share of $3.65 or $3.80, which assumes a share count of between $170 million and $172 million and about $0.07 per share impact in debt issuance.
We expect our non-GAAP tax rate to be 21%. [ph] We expect cash taxes to be approximately $80 million. And along with Ken, I'd like to thank our partners, our customers, and the Fortinet team for all their support and hard work in these difficult and unique times.
Now I'll hand the call back over to Peter to begin the Q&A.