Marcelo Bielsa provides injury update over Leeds United captain Liam Cooper

Cooper pulled a glute muscle shortly before kick-off at Elland Road and was replaced by Gaetano Berardi in a last-minute change to Bielsa’s starting line-up. He is expected to undergo scans tomorrow.

Leeds rode the unexpected alteration to claim a convincing 1-0 victory over Wednesday and take control of the race for the Championoship’s last automatic promotion position but club captain Cooper is at risk of missing some or all of United’s four remaining matches.

The centre-back is nearing the end of his best season to date with Leeds, five years after joining the club from Chesterfield. His form under Bielsa earned him a place in the EFL’s Championship team of the year.

Asked if Cooper had suffered a major injury, Bielsa said: “We don’t think so. He felt a pain like a strained muscle and usually the players don’t suffer an injury in this muscle but with the pain, he couldn’t play.

“I value the fact that Cooper did everything he could to play but at the same time, it’s important to have the experience to tell us that he couldn’t.”

Berardi returned from an injury of his own in February but his start on Saturday was his first in almost almost six months following the torn hamstring he suffered against Ipswich Town in October.

The Swiss defender resisted season-ending surgery with the intention of nursing himself back to full fitness and making himself available for the closing weeks of the season.

He was pitched into a back three against Sheffield Wednesday but Leeds were rarely troubled defensively, producing 28 attempts on goal to the Owls’ eight.

Bielsa said: “Losing Cooper was an uncomfortable situation but Berardi adapted to the game very fast.

“He’s a player who you can trust, a stable player. I’m very happy for him because in this situation he’s an important player for the team.”

Jack Harrison, whose second-half goal settled Saturday’s derby, paid tribute to Cooper’s leadership afterwards, calling him a “great team player.”

Cooper has held the armband at Leeds for two years and is one the verge of skippering United to a long-awaited promotion to the Premier League.

Harrison, United’s young loanee from Manchester City, said: “As a captain you couldn’t ask for anything more. He’s been everything I could have asked for.

“He leads with the way he plays, he’s always motivating the team, he’s a great team player and he has talent. He plays such an important role within the side.”