Pep Guardiola unimpressed despite Bayern going 10 clear

Berlin: Pep Guardiola says his defending champions Bayern Munich must improve on Saturday`s 1-0 win at Hertha Berlin despite opening a 10-point lead at the top of the Bundesliga.

With their nearest rivals Wolfsburg facing Borussia Moenchengladbach on Sunday, Arjen Robben`s first-half goal in Germany`s capital was enough to give Bayern their 10th league win of the season in 13 games.

After suffering their first defeat of the season at Manchester City in the Champions League on Tuesday, their first loss in 23 games, this was a no-frills performance against a limited Berlin side to preserve Bayern`s unbeaten Bundesliga record.

"Perhaps the players were tired after playing 70 minutes with ten men in Manchester," said Guardiola, referring to Mehdi Benatia`s first-half dismissal in Manchester.

"I was happy with the first half performance, but we can improve on the second.

"We played well in the first half, but in the second half we lacked our style, our way of playing.

"It`s always dangerous when you`re only 1-0 up, and Hertha are quick on the break."

Bayern went ahead in the 27th minute at Berlin`s chilly Olympic Stadium when Mario Goetze played Thomas Mueller into the area before Robben hit the top left-hand corner.

"A 1-0 win can happen and we can`t always play well," said Robben. "The second-half wasn`t good, but at least we took three points."

With six months left of the season, Bayern`s march to their third straight Bundesliga title looks virtually unstoppable once again.

But despite nearly 80 percent possession on Saturday, Bayern barely mounted a single shot on goal in the second-half.

"We were 1-0 up, but we didn`t mount a determined effort to get a second, which based on the chances we had, we should have scored in the first half," lamented Bayern`s Germany defender Jerome Boateng.

Bayern host Bayer Leverkusen, who are third in the Bundesliga, next Saturday before welcoming CSKA Moscow in their final Champions League pool match having already reached the last 16 as group winners.