Niko Kovac was frustrated by the referee's decision to give Hoffenheim a first-half penalty in Borussia Dortmund's defeat, claiming it was "not in the spirit of the game".

Dortmund suffered a 2-1 loss to Hoffenheim in the Bundesliga on Saturday, with Andrej Kramaric scoring penalties in the 42nd and 98th minutes, either side of Serhou Guirassy's equaliser.

It was a second consecutive defeat for Dortmund, and it means the door is now open for Bayern Munich to clinch the league title on Sunday, when they face Stuttgart.

However, Kovac felt that the decision to award Hoffenheim's first penalty was harsh, due to Niklas Sule suffering an injury in the build-up.

The defender twisted his knee and could not pull his arm out of the way of the ball, with the penalty awarded following a VAR review while Sule remained on the floor.

"Our player was injured in that action. Giving a penalty in those circumstances isn't in the spirit of the game," Kovac told DAZN.

"It's frustrating for us. We spoke, and ultimately, he hadn't seen it. The VAR contacted him and, as a result, he went out and assessed it as a penalty for handball.

"But I don't know if that's in the spirit of the game. Niki goes down. He braces himself with one hand, and the other has to come down at some point due to gravity.

"That's incredibly unlucky, but according to the rules, it's a penalty."

Dortmund struggled to impose themselves against Hoffenheim, as they managed to get just three of their eight shots on target and accumulated only 0.7 expected goals (xG).

Hoffenheim, meanwhile, maintained their pressure, with 13 attempts (worth 2.1 xG), including four on target and one off the woodwork.

Though Dortmund remain in control of their Champions League fate, Daniel Svensson lamented the team’s lack of urgency after their second straight loss.

"Another bitter defeat," he said. "Of course, it's hard to lose by two penalties.

"But that wasn't exactly our best performance either – not the way we were supposed to play. And then, of course, it's difficult to win games like this when we're playing against strong opponents.

"We have to play with more intensity and move more. In the phases in which we play like this, we are really good and a very difficult opponent to beat. We have to do that over the entire game – and not just one half or 30 minutes."