Spot of bother for Man City's Guardiola

That is, the relatively simple task of converting a penalty.

"This is a problem," a perplexed Guardiola said after seeing Riyad Mahrez fail to score from a spot kick -- again -- in the 0-0 draw at Borussia Dortmund in the Champions League on Tuesday.

Since Guardiola took charge of City in 2016, the team has failed to score 25 of their 80 penalties in all competitions -- excluding shootouts. No Premier League team has a worse record from the penalty spot in that time.

Nine players have stepped up to take regulation penalties in that time, with Mahrez and the now-retired Sergio Aguero the biggest culprits from 12 yards.

Aguero scored 20 of his 28 penalties while Mahrez also has a 71% success rate with 10 scored from 14 attempts.

There have significant misses or saved penalties in recent years.

In the first leg of the Champions League quarter-finals in 2019, Aguero had a penalty saved by Tottenham goalkeeper Hugo Lloris to deny City a crucial away goal before Spurs won 1-0. City exited the competition at that stage on away goals.

Mahrez also smashed a spot kick over the crossbar in the 86th minute in City's 0-0 draw against title rivals Liverpool at Anfield in the Premier League in October 2018.

"We've missed 25 penalties, most of them in the Champions League. That's too much," Guardiola said.

"I always admire their courage, (taking) the responsibility to do it, but of course we've missed a lot of penalties and this is a problem.

"We have to improve otherwise these are the small margins in this competition that could make the difference."

And Guardiola knows all too well about the pain of penalty failures in the Champions League.

When he was at Barcelona, Guardiola saw Lionel Messi strike a penalty against the bar in the second leg of the semifinals against Chelsea in 2012.

It would have put Barcelona 3-1 ahead on the night and 3-2 up on aggregate, and the Spanish team ended up conceding a late goal to get eliminated.

When he was in charge of Bayern Munich, Guardiola saw Thomas Muller have a penalty saved against Atletico Madrid in the second leg of the semifinals in 2016 and his team ultimately went out on the away-goals rule.

At City, Guardiola has previously suggested goalkeeper, Ederson, might be the best penalty-taker at the club. Ederson has yet to take one, however.

And City's problem might be that penalty duties have been spread around too much in Guardiola's time.

"I don't think it's helped that there hasn't been that consistency," former City defender Joleon Lescott told BT Sport. "I think Riyad has been that taker, De Bruyne has taken them, Gundogan, now (Erling) Haaland.

"I think in all the teams we've played in, there's always been one consistent penalty-taker."

Haaland, City's new star striker, was off the field when City were awarded the penalty against Dortmund.

Otherwise he would have taken it, having converted two from two so far in his first season at the club -- most recently against Brighton in the Premier League on Saturday.

Australian Associated Press