Wales prop Nicky Smith may struggle to be fit in time for the Six Nations after suffering an ankle injury playing for the Ospreys.

The loose-head prop – who has become his country’s first choice in recent months – was forced off during his region’s 51-20 European Challenge Cup victory over Stade Francais at the Liberty Stadium.

Ospreys coach Allen Clarke admitted the injury appears a serious one and suggested the 24-yar-old will struggle to make a quick comeback.

“It would have been the perfect result but we lost Nicky Smith, that was the only low light,” said the former Ireland hooker.

“He got over-extended and will have a scan but it certainly looks like he will be missing for a couple of weeks or so.

“They (ankle injuries) never look good. I’m not going to predict the result of the scan but I would suggest it’s not going to be a one or two week injury.”

After shipping half a century of points Stade Francais coach Heyneke Meyer believes his side are out of the quarter-final reckoning.

He said: “We are disappointed to lose but I thought the Ospreys were outstanding especially their set-piece.

“We will put out a stronger side next weekend but we are using this competition to give younger members of our squad an opportunity. Realistically we can’t now qualify from this pool.”

The Ospreys went top of their pool thanks to two tries from Cory Allen and singles from Rhodri Jones, Luke Morgan and Owen Watkin, plus a penalty try.

Sam Davies and James Hook also kicked 19 points between them, while Stade wings Jimmy Yobo and Julien Arias scored tries in either half.