Berlin, Feb 18 (IANS): Top football coaches have to be masterminds at solving problems - and German club Bayern Munich's coach Pep Guardiola is a mastermind at conjuring surprising solutions to basic problems.

Ahead of their frustrating 0-0 draw in the first leg of the Champions League pre-quarterfinal by Ukrainian club Shakhtar Donetsk in Lviv Tuesday, Bayern were faced with a conundrum of fixing their shaky defence, which was the biggest impediment in their hopes of reaching the final of Europe's premier football tournament this season, reports Xinhua.

Guardiola found a possible and surprising solution to his team's weakness, which has been obvious this season. He employed midfielder David Alaba, also a left-back in recent games, as Bayern's second central defender alongside Jerome Boateng, both pacy players.

At right and left back were Rafinha and Juan Bernat respectively. For 65 minutes of the match against Donetsk, Bayern were well-organised and dominated the game without giving too much space for Donetsk to counter-attack.

Things worked out in defence perfectly but Bayern it opened up a new problem. Bayern had trouble going forward.

With the draw, the German Champions now have to score and win in the second leg in Munich March 11 to advance to the quarters.

"It's a highly dangerous result for us," Matthias Sammer, Bayern's director of football, said Wednesday.

"Now the truth is: If you want to get to the next round you have to win at least one game. We've solved the problem of being prone to counter-attacks but we have a lot of space to fill. It's not where we want the team to be and it will take some hard work to get in best shape."

Bayern midfielder Mario Goetze admitted: "We had problems in the last third of the pitch. We'll have to improve and quickly."

Experts felt Bayern's game lacked speed and on top, particularly with Bastian Schweinsteiger and Xabi Alonso in charge of the central midfield, it was impossible for them to be mobile.

The problem compounded when midfielder Alonso was sent off after being shown a second yellow card.

Until then Alonso had done a lot of important defensive work, which was vital to Guardiola's tactical system (4-2-2-1 or 4-1-2-2-1) which seeks a healthy balance between attacking and defensive duties.

Bayern also found it difficult to convert the scoring chances they received with striker Thomas Mueller far from his incisive self.

Not scoring a goal despite having 85 percent of ball possession against a defensive-minded team doesn't reflect the attacking firepower of Bayern, who were led in their search of goals by Dutchman Arjen Robben.

Despite failing to score, the absence of Polish striker Robert Lewandowski from the starting eleven will continue to be debated.

Some experts have justified his absence due to his below-par performance in the season so far, scoring only eight times in 21 Bundesliga games.

Bayern have to score to win against Shakhtar and advance to the Champions League quarters.

And to do that Guardiola has to solve the "goal problem" with his defence giving him some respite, at least temporarily.