Xabi Alonso says the injury that forced Patrik Schick off during Bayer Leverkusen's win over Bayern Munich "doesn't look good".

Schick was substituted an hour into Tuesday's DFB-Pokal tie, having only been introduced at half-time, after sustaining an injury off the ball.

The forward has scored nine goals for Leverkusen in all competitions this season, a tally only Florian Wirtz can match.

Asked about Schick's injury after his side's 1-0 victory at the Allianz Arena, head coach Alonso said: "Patrik felt something in his calf.

"He's being examined and we'll see. It doesn't look good at the moment."

Schick played the full 90 minutes for Leverkusen and scored the winner in Saturday's 2-1 Bundesliga win at Union Berlin.

Asked by Bild about his substitution against Bayern, the Czech international suggested he was already carrying a knock.

"I suffered a thigh problem in Berlin. I can't say more now, I don't know," he said.

Nathan Tella scored the only goal of the last-16 tie in the 69th minute, with holders Leverkusen profiting from Manuel Neuer's first-half dismissal.

The reigning German champions have scored in 35 successive DFB-Pokal away games, yet they were not at their best in Bavaria.

Despite having less possession and registering fewer shots than their opponents, Leverkusen got the job done to advance to the quarter-finals.

"It was not our best game with the ball or even with an extra man but we applied our plan," defender Jonathan Tah said.

"It was not immediately easy to adapt to having an extra man. We did not use it in the first half. We were too hectic and wanted to score quickly.

"We did not do it perfectly today but we were effective and then Nathan headed in the winner."

Alonso has now won all nine of his games as a head coach in the competition – only Louis van Gaal and Pep Guardiola (both 10) have gone longer unbeaten at the start of their coaching careers.