Ireland skipper Brian O'Driscoll has revealed he was troubled by a virus during Saturday's 20-16 RBS 6 Nations victory over England at Twickenham.
O'Driscoll missed the eve-of-match captain's run after being struck by the illness and was still not operating at full throttle by the time the match started.
The Lions centre's difficulty failed to prevent Ireland from securing their sixth victory over England in their last seven contests, a result that thrust them back into title contention.
“I didn't really get a chance to talk to anyone at the (post-match) dinner,” said O'Driscoll in his blog on the Irish Rugby Football Union's official website.
“That was probably as much to do with the way I was feeling after contracting a bug/virus prior to the match. I wasn't very talkative.
“I was happy enough just making the game, a minor achievement in my own head.
“I was thankful to see the rain because it slowed the game down a bit.
“The illness was definitely a distraction and I was grateful to Paul O'Connell and Jamie Heaslip, amongst others, who did most of the talking prior to the match.
“I think I managed to camouflage the fact that I wasn't feeling great on the pitch reasonably well.”
While O'Driscoll refused to succumb to the virus, he was unable to shake off the blow to the head he sustained in the 64th minute of the Twickenham showdown.
The 31-year-old was accidentally struck by the knee of team-mate O'Connell and was stretchered off, but has been cleared to face Wales on Saturday week.
“What does it say about me that I got a better score on the cognitive test I undertook after Twickenham last weekend than the pre-season equivalent? Perhaps I'm getting smarter with age.” he said.
“Seriously though, it is a rigorous examination of concentration and memory and for a moment or two during the test I was transported be back to Mr Byrne's class in primary school.
“You do have to have all your faculties to pass muster.”
Meanwhile, full back Rob Kearney took part in a non-contact training session yesterday and coach Declan Kidney expects to have the Louth man available for the game agaisnt Wales.
Kearney's recovery means Kidney will have to decide between restoring the Lions tourist to the No 15 shirt or sticking with Geordan Murphy, who put in a solid shift in the victory at Twickenham.