Bayern Munich striker Robert Lewandowski admitted the Bavarian giants had Tuesday's Champions League quarter-final, first-leg, against Benfica firmly on their minds after their below-par 1-0 win over Eintracht Frankfurt.

Pep Guardiola's Bayern had to rely on a moment of genius from winger Franck Ribery, whose spectacular 20th minute bicycle kick sealed the Bundesliga leaders' victory on Saturday.

Lewandowski, the league's top scorer, had a quiet afternoon, failing to add to his tally of 25 Bundesliga goals this season and came off with 19 minutes to go at Munich's Allianz Arena.

"We definitely had the Champions League game against Benfica on Tuesday in our heads," Lewandowski admitted openly as they failed to convert their 21 shots into more goals against second-from-bottom Frankfurt.

"We have to play much, much better then than we did today.

"That wasn't a good games for the fans to watch."

Bayern chairman Karl-Heinz Rummenigge has warned they can ill afford to rely on another super strike from Ribery against the Portuguese league leaders.

"What was most important was the three goals," said Rummenigge.

"But skills like that won't be enough on Tuesday.

"(Some of the media) have written the (Benfica) game off as a bye into the next round, but it's not a foregone conclusion.

"We have to play much better and be very concentrated."

Nevertheless, Bayern are five points clear in Germany's top flight with six games left.

They remain on course to become the first club to win four straight German league titles.

Bayern also claimed a league record with their eighth straight clean sheet against Eintracht Frankfurt.

No other club has managed the feat as many times in a row against the same opposition in the Bundesliga.

But even Guardiola was talking about Benfica just minutes after the final whistle against Frankfurt.

"I am very impressed with Benfica," said the Spaniard.

"Here in Germany, everyone is very confident, but it will be difficult to reach the semi-finals.

"We started well (against Frankfurt) and had some good moves, nt just that crazy goal from Franck.

"Things would have got easier with a second goal, but now our full focus in on Benfica.

"I hope for a better performance."