Liverpool suffered an injury scare to defender Andy Robertson in their 1-1 friendly draw against Athletic Bilbao on Sunday.

The club's penultimate preseason match was dampened when Robertson, 27, appeared to sustain a serious ankle injury before half-time which saw him replaced.

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"We obviously don't know in the moment how serious it is," Liverpool boss Jurgen Klopp told a postmatch news conference. "It was pretty painful and that's why Andy went off.

"You probably saw it on the TV pictures better than we did, but he got the ball, the ball on the front of his foot, [and] twisted the ankle.

"The pain settled already, but we cannot say anything further without further assessment tomorrow. He has to get a scan and then we will know more."

Liverpool went ahead in the first half through a Diogo Jota strike but the LaLiga side replied in the second half with Alex Berenguer goal to rescue a draw.

The match was played in front of Anfield at 75% capacity -- the biggest crowd at the ground since the start of the coronavirus pandemic.

Kickoff was delayed by 30 minutes after thousands of supporters queued outside to enter the stadium.

There was good news for Liverpool as Virgil van Dijk started the game and received a standing ovation when he was substituted after 71 minutes.

Van Dijk, who missed the majority of last season with an ACL injury, impressed as well as Joel Matip and Naby Keita who also spent long spells on the sidelines last term.

Liverpool take on Osasuna in their final preseason match before they begin their Premier League campaign away at Norwich City on Aug. 14. Athletic face a trip to Elche on Aug. 16 for their first league match.