Wales are sweating on skipper Sam Warburton's fitness after he took a blow to his knee during the 20-13 Six Nations victory over France in Paris.
Wales' fourth win in succession against Les Bleus kept them in the title mix, with their next game in two weeks' time being at home to reigning Six Nations champions Ireland.
Warburton, though, went off in the second half at the Stade de France and went back to the team hotel instead of attending the post-match dinner in central Paris.
“My knee just swelled up and I couldn’t run at full pelt,” Warburton said.
“It is just a bit of swelling. I will be up every two hours tonight icing it, and reassess tomorrow morning.”
Wales head coach Warren Gatland added: "With Sam's knee, we are not too sure how serious that is.
“He won’t be going to the dinner tonight, he is going back to the hotel and we are just hoping it is not too serious.
“He has just taken a knock on the knee, and it is probably just waiting for 12 hours or so.”
Warburton watched the closing stages as Wales prevailed through outhalf Dan Biggar's first try for his country and five Leigh Halfpenny penalties.
France replied through a Brice Dulin touchdown and eight points from the boot of Camille Lopez, but it was Wales' forwards who built an impressive victory platform.
“We were disappointed with our second-half performance against England (three weeks ago). We were written off by a lot of people,” Gatland said.
“There was an improvement against Scotland, and it was another step up tonight. We are back in contention, although we need a couple of results to go our way.
“In terms of the performance, I thought the forwards were outstanding. The lineout was excellent and we scrummaged well.
“And we went out and played some rugby. The better team deserved to win. If we can win against Ireland, we are potentially in with a chance.
“We spoke beforehand that Wales have not achieved four wins in a row against France since the 1950s, so there was potential to create something that was a bit special today.
“I thought our composure and experience was what got us over the line. That was satisfying. I think we grew and matured as a team a heck of a lot tonight.”
Gatland also paid tribute to Wales' sizeable France-based contingent, players like Halfpenny, centre Jamie Roberts and lock Luke Charteris, who all delivered outstanding displays.
“I think the advantage was that our French-based players were able to give an insight into a number of the French players, having been team-mates or played against certain players,” he added.
“I think for the Welsh players based over here in France it was probably as much them wanting to prove their worth and value and the reason why they are over here. In terms of that self-motivation, it was wanting to perform.
“I thought some of Jamie Roberts’s carrying was excellent, the goalkicking of Leigh Halfpenny was potentially the difference, and Luke Charteris was outstanding defensively in lineouts and rucks.
“I thought there was an edge about those players, and they did a good job for us.
“It is a massive game for us at home against Ireland in a couple of weeks. Ireland are clinical at what they do, they don’t make a lot of mistakes.”
Reflecting on a defeat that has realistically cost his team any chance of contesting Six Nations silverware this season, France coach Philippe Saint-Andre said: “International rugby is all about the little things. You cannot spend the whole match defending, and it is very difficult to win with 50 per cent goal-kicking. We really need to work on the basic skills.
“Teams like Wales and Ireland know exactly how to play these type of games. We made some really sloppy mistakes, and with a goal-kicker like Leigh Halfpenny it meant it made it very difficult for ourselves.”
