A serious-looking injury to captain Alex Greenwood overshadowed Manchester City’s 2-0 Champions League victory over St Polten.

The England defender went down in obvious pain during the first half clutching her left knee and covered her face with her shirt as she was carried off on a stretcher.

City will hope the injury is not as bad as it appeared, but it marred a night which saw a debut to remember from 18-year-old Lily Murphy, who only signed her first professional contract last week.

The teenage City fan was lively throughout and held her arms aloft in delight when she tapped in the opening goal in the 55th minute, with Kerstin Casparij also scoring her first goal for the club.

The victory maintained Gareth Taylor’s side’s perfect record in the competition, although Barcelona’s victory over Hammarby means they are not yet assured of top spot in the group ahead of a trip to Catalonia next week.

Khadija Shaw was rested for the match at the Joie Stadium, paving the way for Murphy to make her first start, and the academy graduate came close in only the fifth minute, breaking through and sending in a shot that was saved by Carina Schulter.

Sophie Hillebrand shot over with a rare chance for St Polten before the mood in the stadium changed when Greenwood went down following a challenge with Melanie Brunnthaler.

Following lengthy treatment she was replaced by Laia Aleixandri and City briefly struggled to regain their composure, with keeper Ayaka Yamashita nearly caught out as she waited to clear the ball.

The breakthrough came 10 minutes into the second half, Aoba Fujino’s cross from the left somehow finding its way across to Murphy, who could not miss.

The teenager was irrepressible and her cross nearly set up a second for Casparij, who headed just past a post.

Murphy then shot just wide before, in the 66th minute, Fujino again crossed from the left and this time Casparij arrived in the centre of the box to tuck home.

City could have scored more but had to settle for two in a game they completely dominated.