Taking a closer look at the numbers, 1Q18 EPS came in at $0.56, beating the Capital IQ Consensus by $0.03, with revenue up 19% year/year to $677 million, also ahead of the $647.4 million consensus. This quarter marked the first time since 2Q16 that it beat on both the top and bottom lines. Furthermore, its 19.0% topline growth was its strongest revenue growth in at least eight quarters.
While the headline numbers were solid, so too was RHT's performance in operating margin, cash flow, and billings. Each one of these metrics came in ahead of expectations as well. Specifically, operating margin was 20.5%, cash flow grew 11% year/year to $258 million, and billings increased by a solid 20%.
There are a couple primary catalysts that drove this performance. The most significant of these catalysts is that IT departments are increasingly looking to update their infrastructure to the hybrid cloud. The transition is generating robust demand for RHT's core business, RHEL (Red Hat Enterprise Linux). Larger enterprise customers in particular are looking to make this transition. Case and point is that all of RHT's top 25 deals renewed during Q1 and in aggregate, renewed at more than 120% of their prior annual purchase.
RHT also has a number of newer products that are moving the needle, including OpenShift and OpenStack. In regards to OpenShift, RHT recently announced an extended partnership with Amazon Web Services to further integrate OpenShift -- its container platform -- as a service broker to hybrid cloud users. Containers are technologies that allow users to package and isolate applications with their entire run-time environment. This makes it easier to move the contained application between environments (development, test, production) while retaining full functionality.
And finally, RHT also recently launched its latest version of OpenStack Platform 11 with one of the key enhancements being its deployment tool, making deploying and upgrading private clouds easier.