Wasps boss Dai Young delivered a positive fitness bulletin on James Haskell after the England flanker's long-awaited comeback from injury lasted less than a minute.
Second-half substitute Haskell appeared to be knocked out following a tackle on Leicester full-back Freddie Burns as Wasps claimed a gripping 22-16 Aviva Premiership victory at the Ricoh Arena.
He was then helped off, having featured for just 49 seconds in his first appearance since suffering a serious toe injury during England's successful Australia tour last summer.
And while the initial signs are good, Haskell will face a fitness race against time for next Saturday's key European Champions Cup clash against French heavyweights Toulouse.
"He is totally fine now," Wasps rugby director Young said. "He had a real big hit and had a bang on the head, so he has got to go through the protocols.
"It was the best '36-second' comeback ever, so he is having a bit of a ribbing off the boys, but all jokes aside, thankfully he is okay. He took a nasty bang to the head.
"He went in low to make the tackle and it was pretty much head on body.
"We've all been really eager to get him back on the field and he's had a big build-up, but he is totally fine, laughing and joking and having a bit of banter.
"He has got to come through all the necessary protocols. It's a six-day protocol, so he has got to tick all the boxes. It's certainly touch and go [for Toulouse] - it's certainly going to be tight."
Wasps, 19-0 up before half-time, courtesy of tries by Christian Wade, Tommy Taylor and Dan Robson, found themselves hanging on as Leicester began life after Richard Cockerill by responding superbly in front of a 27,930 crowd.
Cockerill lost his job as rugby director last Monday, with head coach Aaron Mauger taking interim charge, and the New Zealander was thrilled by Tigers' second-half response.
Centre Peter Betham scored a try, with Owen Williams adding two penalties, while Burns slotted a penalty and conversion before Wasps edged a thrilling encounter through a late Jimmy Gopperth penalty - following two earlier conversions - immediately after a yellow card for Tigers' England prop Dan Cole to see Wasps home and reclaim Premiership top spot.
"The first half, we came out of the blocks, got some quick ball to play off and we were probably disappointed that we didn't come away with some more points on the board," Young added. "Once you give a team like Leicester a bit of momentum, it's very hard to snatch it back. I thought we were in total control in the first half, and pretty much hanging on for dear life in the last 10 minutes.
"You know the players Leicester have got, they are a proud bunch and never know when they are beaten.
"I am pleased we have won - I don't want to downplay that - but we constantly talk about learning from every game."
After a testing week for Leicester, Mauger was understandably delighted with the fightback, albeit one that ended with the consolation prize of a losing bonus point.
"I don't think you could ever question the character of our guys," he said.
"We talked about playing for each other before we got on the bus. I was really proud of the way the guys responded in the second half.
"I thought we put ourselves in a situation to win the game. There were probably a couple of moments which cost us.
"There was a lot of emotion going around, especially in the first part of the week, but everyone has taken responsibility for the situation.
"We have lost some good men this season due to our performances, and we are all responsible for that.
"I thought they stepped up, and to a man they were all outstanding today. They all gave it everything, and played with passion and commitment.
"Although we might have stumbled along at times this season, we are actually not far off those teams at the top. We will take a lot of belief out of that."