Director of rugby Declan Kidney praised London Irish's 'heroic defence' as they just clung on to mark their Premiership return with a superb 29-26 win at Wasps.
Blair Cowan, Albert Tuisue and Ollie Hassell-Collins scored their tries with Paddy Jackson adding a conversion and four penalties.
Jackson missed three others, which on another day could have proved costly, but Kidney said: "We defended stoically and showed great resilience as we have a great work ethic.
"We took our chances and the 10 points we scored just after half-time proved crucial.
"Paddy (Jackson) missed a couple of three-foot putts but fortunately he recovered to kick a few others.
"We were pleased with the performances of our back three as they are all our Academy products and it shows that players want to stay with the club."
For Wasps, Zach Kibirige scored two tries and Dan Robson one, with Lima Sopoaga kicking two penalties and a conversion.
Jacob Umaga added a late penalty to secure a bonus point for his side but their Director of Rugby, Dai Young, was unhappy with his side's performance.
Young said: "We should have been better than that as we gave away some soft tries with two conceded from turnovers.
"We didn't get much ball in the first half and when we did, we panicked. We left ourselves with a mountain to club and I'm frustrated that we put ourselves in that position.
"The second half was a reversal of the first as we had plenty of the ball but we weren't good enough to change the scoreline.
"We knew it would be tough against them as the promoted side has won on the opening day in three of the last four seasons, and parts of their game were top drawer.
"There were a few positives out there with Zach Kibirige finishing fantastically."
With eight minutes remaining, Wasps trailed 29-20 and Irish lock, Ruan Botha, was in the sin-bin. They were then awarded a penalty, which Umaga kicked, but an attacking line-out may have proved the better option.
Young disagreed and said: "It wasn't my call but I'm happy with it as we had at least three opportunities to score in the final two minutes and should have taken at least one of them."
Wasps skipper, Dan Robson, said: "It's massively frustrating to lose at home as we are trying to build a fortress at the Ricoh.
"I'm pretty dejected as we were always chasing the game and didn't make them work hard enough for their points."