Liverpool will assess star man Mohamed Salah after he was substituted early in the second half of Wednesday's dominant 3-0 victory over Manchester City in the Champions League.
Salah was at his brilliant best during the opening period at Anfield, breaking the deadlock after Ederson saved from Roberto Firmino, and crossing for Sadio Mane to head home the Reds' third and establish a vice-like grip on the quarter-final tie.
However, the Egypt forward's capacity to add to his 38-goal haul this season in Saturday's Merseyside derby and next Tuesday's second leg in Manchester has been placed in doubt – even if the problem does not appear to be serious.
"At the moment, he comes to the sideline and says he feels sometimes something and that is enough for me to not even ask the doc, but take him off the pitch," Liverpool manager Jürgen Klopp told reporters afterwards.
"After the game I asked him and he said he feels fine so we have to wait for the real diagnosis, not Mo’s diagnosis."
Blistering attacking play led by Salah was always Liverpool's most likely root to victory but Klopp took time to single out a defensive display that prevented City's own usually rampant forward line from registering a shot on target.
"They didn't play bad," Klopp said, having again tasted victory against a Pep Guardiola side.
"They didn't create the usual number of chances because we defend in a lot of moments outstandingly well.
"Trent [Alexander-Arnold] had an outstanding game, Robbo [Andrew Robertson] on the other side, both centre-halves had very good games.
"Our three midfielders were absolutely brilliant, our three offensive guys were in the right spaces and supported them."