Bayern Munich seized on the uncertainty sweeping through Arsenal to claim a 3-1 victory in the first leg of their Champions League last-16 match on Tuesday, virtually booking the German side a place in the quarterfinals.

Goals by Toni Kroos and Thomas Mueller in the opening 21 minutes did the early damage for Bayern — a beaten finalist in two of the last three years — before Mario Mandzukic sealed victory with a bundled third in the 77th.

Former Bayern forward Lukas Podolski had given Arsenal hope by making it 2-1 in the 55th but Bayern was well worth the win, and should have scored more in an embarrassingly one-sided first half where the visitors cut through their defensively inept opponents at will.

The second leg is in Germany on March 13.

Bayern has reacted superbly to the trauma of losing last season's final at Chelsea on penalties at its own Allianz Arena, surging into a 15-point lead in the Bundesliga and qualifying easily from its Champions League group.

Coach Jupp Heynckes has even labeled the team the best in Bayern's history, and it showed why against an Arsenal side in the midst of the most trying season of Arsene Wenger's 17-year reign. Winning the Champions League is the English club's last chance of ending an eight-season trophy drought.

Messy defence

Defensively, Arsenal was a mess, with centre backs Per Mertesacker and Laurent Koscielny looking like accidents waiting to happen. The first goal sprung from their lax inter-passing in front of their own penalty box, with Bayern collecting a rushed, errant clearance from Koscielny before Mueller crossed for Kroos to crash home a volley that skidded off the turf and into the net from 18 yards (meters).

Mueller then benefited from more hesitant defending for the second, the lanky forward on hand to poke the ball high into an unguarded net after goalkeeper Wojciech Szczesny parried out a header from an unmarked Daniel Van Buyten.

With Kroos, Javi Martinez and Bastian Schweinsteiger dominating midfield with their hulking presence and Arsenal's passing awry all over the pitch, Bayern was in cruise control with barely a quarter of the match gone and its record of not conceding in 2013 wasn't looking in danger of ending.

Theo Walcott started as the lone striker for the hosts but he received little service in the first half, unlike opposite number Mandzukic, who headed just wide on the stroke of halftime from Philipp Lahm's right-wing cross.

Arsenal's players were losing their heads — Bacary Sagna and Mikel Arteta picked up petulant bookings — and they were jeered off at halftime as Bayern supporters belted out another rendition of "Football's Coming Home" in English. Home manager Arsene Wenger, who was tetchy throughout his pre-match press conference, had the look of a beaten man.

Things looked up at the start of the second half, though, and Podolski capped a period of gentle Arsenal pressure by heading into an empty net after Jack Wilshere's inswinging corner evaded a raft of players in the six-yard box — including flapping Bayern goalkeeper Manuel Neuer.

Wilshere was finally making his presence felt and Bayern's early spark faded as Arsenal monopolized possession. Olivier Giroud, on as a 71st-minute substitute, shot straight at Neuer in Arsenal's other good chance.

However, Bayern had the last laugh when Mandzukic finished a sweeping move by bundling in Lahm's low cross at the far post, the ball looping up off the Croatian's heel and beyond Szczesny.

Porto wins at home

A second-half goal from Joao Moutinho gave Porto a 1-0 win over Malaga, ending the Spanish club's unbeaten run in the competition and giving the Portuguese team a slender advantage for the return leg next month.

After almost an hour of sustained pressure, Porto's breakthrough came when defender Alex Sandro ran at the visitor's defence on the left flank and poked a pass through for Portugal midfielder Moutinho to side-foot the ball between Malaga goalkeeper Willy's legs.

sp-300-moutinho

Porto's midfielder Joao Moutinho, right, celebrates after scoring against Malaga. (Miguel Riopa/AFP/Getty Images)

In the other last 16 game taking place Tuesday, Bayern Munich beat Arsenal 3-1 in London.

The Iberian duel in northern Portugal produced a tight game with few clear goalscoring chances.

Porto, a two-time European champion in the knockout round for the seventh time in 10 years, was the hungriest team and mostly dictated the run of play.

Malaga, making its debut in the top-tier European competition and playing in Portugal after surprisingly winning its group earlier in the tournament, was happy to keep possession and cautious in attack as it held out for better chances in southern Spain.

"We were dominant, we pressured, we didn't let them play their game," Porto coach Vitor Pereira said. "It's just a shame we didn't get a second goal."

Porto came out fighting, with Marat Izmailov producing a low drive in the fourth minute that had Willy diving sharply to his left and central defender Fernando at the back post almost connecting with Silvestre Varela's flicked header in the 18th.

Jackson Martinez was guilty of squandering Porto's best chances. The Colombian striker, who is the Portuguese league's top scorer this season with 20 goals in 19 games, was denied from short range by Sergio Sanchez in the 32nd minute and then failed to control the ball inside the Malaga area five minutes later.

Sanchez threatened down the right flank in the 50th before Sandro blocked his pass inside the Porto area, but Izmailov soon came closer when his miscued shot at the back post bounced just wide of the post.

Moutinho broke the deadlock in the 56th.

Porto heaped pressure on the Malaga defence which held firm ahead of the March 13 decider.