After winning their first three games German champions Bayern were in the box seat at the top but, while their perfect record came to an end, the point is enough to send them into the knockout phase.

Bayern top the group on ten points and one more victory will see them go into the last 16 as group winners.

Bayern coach Felix Magath said it was crucial that his side finished top to ensure they have the second leg at home in the knockout stage.

"We struggled tonight and that was our worst display so far," said Magath. "We are through but I want top spot as we saw what an advantage it is from AC Milan last year."

Last season AC Milan used home advantage to crush Bayern 4-1 in the second leg of their last 16 Champions League duel.

Despite the delight at progressing Bayern fans jeered their team off after the final whistle and Belgian international Daniel van Buyten understood their frustration.

"That was our poorest performance in the Champions League this season but it was another clean sheet and we are in the knockout stage," said van Buyten.

"Of course the fans want goals and that is what they pay their money for -- but it was not our day."

With German international Bastian Schweinsteiger suspended and Dutch midfielder Marc van Bommel injured, coach Magath was forced to rejig his team.

Defender Christian Lell, a 22-year-old local lad from Munich, was handed his Champions League debut at right back as Willy Sagnol moved forward into midfield.

Bayern could have taken the lead as early as the 11th minute with Dutch forward Roy Makaay driving his shot inches wide of the post after a brilliant reverse pass from Sagnol.

Makaay, the club's record signing at 18.75 million euros, had his team's other chance close to half-time but his tame shot was easily saved by Sporting goalkeeper Ricardo.

The Portuguese visitors had their moments of danger but often overplayed at the critical stage.

Bayern looked solid at the back despite the absence of injured Brazilian international centre-back Lucio and kept another clean sheet and they have yet to concede a goal in Europe's flagship competition this season.

Bayern, winners of this competition in 2001, lead the standings four points ahead of Inter Milan who defeated Spartak Moscow 1-0 earlier on Tuesday. Spartak -- winless in their last 22 Champions League matches -- are Bayern's next opponents in the Russian capital on November 22.