Ethan Nwaneri was substituted in Borussia Dortmund's Champions League clash with Villarreal, but manager Niko Kovac insisted the decision was not performance-related.

Ethan Nwaneri was faced with being substituted by Borussia Dortmund after coming off the bench earlier in the match in their victory over Villarreal in the Champions League. However, Niko Kovac has insisted the decision was no cause for concern, with the teenager delivering a 'really good' display.

Nwaneri, on loan at BVB from Arsenal, was introduced after just 27 minutes when Konstantinos Karetsas required medical attention for what was subsequently described as a circulation issue. The 18-year-old was carried from the field on a stretcher before being taken immediately to the hospital in distressing scenes at the Westfalenstadion.

Karetsas, who joined Dortmund from Genk in the summer, was making his fifth appearance for the club. The German side said: "Konstantinos Karetsas had to leave the pitch in the game against Villarreal due to circulation problems. Kosta is doing as well as can be expected given the circumstances, and he is on his way to the hospital for further examinations."

The unfortunate issue provided Nwaneri with an opportunity to impress, and he looked to take it as Dortmund secured a 3-2 victory. The youngster registered the joint-most shots, joint-most dribbles and joint-most tackles for the Bundesliga side during his spell on the field.

Despite that influence, Nwaneri was withdrawn after Serhou Guirassy fired Dortmund 2-1 in front. Former Chelsea and Aston Villa ace Carney Chukwuemeka came on for the 19-year-old in the 82nd minute, after Nwaneri had been on the pitch less than 60 minutes.

It is normally a source of embarrassment for players to be subbed on and off in the same match, but the Dortmund boss insisted that Nwaneri clocked up a comparable amount of playing time as he would have done had he been in the starting XI. "He gave everything. If he had started the game, he probably would have come off around the 60th minute," Kovac said.

When questioned whether the decision was linked to Nwaneri's performance, he added: "Quite the opposite, he was really good," Kovac emphasised.

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"It was great that he was able to have an impact on the team in such a short time."

After the final whistle, Nwaneri appeared far from downbeat, taking to Instagram to reflect on the victory, writing: "Great team spirit, onto Saturday."

His post was met with a wave of backing from fellow players, with Jobe Bellingham and Waldemar Anton both responding with a string of smiling face with heart-eyes emojis.

Chukwuemeka chimed in with: "My boyy," accompanied by a red heart, while forward Fabio Silva kept it simple, posting: "So good."