Porto punished two goalkeeping blunders to beat Arsenal 2-1 and Bayern Munich's late winning goal against 10-man Fiorentina was clearly offside on a dramatic night in the Champions League. Backup Arsenal goalkeeper Lukasz Fabianski fumbled a cross from Silvestre Varela into his own net to concede the opening goal and then handled a backpass by teammate Sol Campbell to hand Porto its second goal. Arsenal was without five first-team regulars including goalkeeper Manuel Almunia and Russia forward Andrey Arshavin. Falcao pounced in the 51st minute, scoring following a quick free kick inside the penalty area after Arsenal defender Sol Campbell had made a backpass to goalkeeper Lukasz Fabianski, who picked the ball up. It was the Colombian's fourth goal in seven Champions League games this season. The home team took the lead in the 11th minute when stand-in goalie Fabianski, who had strayed too far off his line, dived backwards to bundle a low cross by Silvestre Varela into the net. Campbell, making his first appearance in Europe in four years since his return to Arsenal, equalized with a header seven minutes later. Campbell, unmarked, found the roof of the net from short range to score what could be an important away goal. The return leg in London is on March 9. Bayern made it 13 victories in a row in all competitions by beating Fiorentina 2-1 in Munich. Arjen Robben fired the German side into a halftime lead with a penalty in the third minute of first-half stoppage time, the Dutch winger scoring for the sixth game in a row. Per Kroldrup, who had given away the penalty for a foul on Franck Ribery, replied for Fiorentina early in the second half but Miroslav Klose headed the winner in the 89th minute from an offside position. The Italian side by that time had been reduced to 10 men, midfielder Massimo Gobbi sent off by referee Tom Henning Ovebro in the 73rd minute for a bodycheck on Robben. Manchester United came from behind to win 3-2 at AC Milan and Lyon beat nine-time European champion Real Madrid 1-0 in Tuesday's first-leg games. The remaining four first-leg matches are next week – Olympiakos hosts Bordeaux and defending champion Barcelona goes to Stuttgart. Inter Milan coach Jose Mourinho faces Chelsea, the club he guided to two Premier League titles in a row, and CSKA Moscow hosts Sevilla. Turkmenistan holds S. Korea World Cup finalist South Korea was held to a 1-1 draw by 10-man Turkmenistan in their opening group game of the AFC Challenge Cup in Colombo Wednesday. The Korean Under-23 team recovered from an early goal by Mamedaly by drawing level through a free-kick by Ryang Yong-gi before Turkmenistan was reduced to 10 players. South Korea has been drawn alongside Argentina, Nigeria and Greece in Group B at this year's World Cup in South Africa.