Barcelona captain Carles Puyol has admitted that an injury to Lionel Messi overshadowed their confirmation as Champions League group winners.

Messi was introduced as a second-half substitute during Wednesday's goalless draw with Benfica, but was stretchered off in the closing stages after hurting his knee.

Puyol revealed that Messi was undergoing tests immediately after the match and backed the Argentine forward to make a swift return.

He told UEFA.com: "Lionel Messi is undergoing some tests, but hopefully it is not anything.

"Clearly this is the worst news of the night and hopefully he will be back with us at 100%. We tried to play as we can, we tried, we made chances and it was an open game."

Messi has four games left to equal Gerd Muller's record of 85 goals in a calendar year, with the Barca talisman currently stuck on 84.