5 things to know about Arsenal vs. Bayern Munich

LONDON (AP) — Bayern Munich returns to London for the first time since winning its fifth Champions League title at Wembley last May to take on Arsenal in the round-of-16 on Wednesday.

The Champions League victory was the pinnacle of a treble-winning campaign for Bayern, which looks capable of matching last season's achievement under Pep Guardiola. They are unbeaten in the Bundesliga, winning 19 of 21 matches, and are 16 points clear of Bayer Leverkusen in second.

"Bayern were very strong last year, they achieved everything," Arsenal's Germany defender Per Metersacker said. "But with Guardiola in charge, they look even sharper."

Arsenal's confidence has been boosted by taking revenge on Liverpool for a 5-1 thrashing in the Premier League by knocking them out of the FA Cup with a 2-1 win on Sunday. Do the Gunners still have enough to get the better of defending champion Bayern over two games? Here are five things to know about Wednesday's match.

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BAYERN LOVES LUCKY LONDON: Bayern is making its fourth visit in a year to England, which holds nothing but fond memories for the German leader. It beat Manchester City 3-1 in the group stage this season, won the league final 2-1 last May against Borussia Dortmund at Wembley, and won 3-1 against Arsenal at the Emirates in the last 16 last season. "It's great to be going back again," said Arjen Robben, who scored the winner against Dortmund. Bayern chairman Karl-Heinz Rummenigge said, "We've got terrific memories of playing Arsenal. And the attraction of London is even greater after winning the final against Dortmund."

NO RIBERY, SHAQIRI? NO PROBLEM: Bayern is without attacking midfielders Franck Ribery and Xherdan Shaqiri. Ribery is recovering from surgery on a ruptured buttock muscle, and Shaqiri ruptured a right thigh muscle after scoring a brace in the 4-0 win over Freiburg on Saturday. But Arsenal will still have to nullify the threat of Arjen Robben, Mario Goetze and Thomas Mueller, as well as stopping midfielder Bastian Schweinsteiger from dictating play. "They don't just have 11 players, they have nearly two teams who can compete on a Champions League level, so they are the toughest opponent you can get in Europe," Mertersacker said.

OXLADE-CHAMBERLAIN ARSENAL'S KEY? Since scoring twice on his return from injury against Crystal Palace, midfielder Alex Oxlade-Chamberlain has been Arsenal's most in-form player. He opened the scoring against Liverpool on Sunday before providing an assist for the second goal by Lukas Podolski. He poses an unknown quantity for Bayern, too. He played only 18 minutes when the teams met at the same stage last season, when Arsenal won the first leg 2-0 at Allianz Arena. He was an unused substitute when Bayern overturned the two-goal deficit to win 3-1 and knock Arsenal out on away goals.

PLAYERS ARE RESTED AND READY: Both sides rested some of their best players before the first leg. Mario Goetze, Bastian Schweinsteiger, Thiago Alcantara, David Alaba and Jerome Boateng were all on the substitute bench as Bayern demolished Freiburg 4-0. Captain Phillipp Lahm promised Bayern is looking to go into the second leg with an advantage. "We won't be playing for a goalless draw," Lahm said. Arsene Wenger took Jack Wilshere, Olivier Giroud, Santi Cazorla, Bacary Sagna and Wojciech Szczesny out of the firing line on Sunday as he too had one eye on making sure his players were fresh for the game. "Tomorrow the heroes will be on the pitch, not on the bench." Wenger said on Tuesday.

HISTORY ON BAYERN'S SIDE: Bayern has knocked Arsenal out of Europe twice before, both times at the last-16 stage. As well as winning on away goals after drawing 3-3 on aggregate last year, Bayern was victorious in 2004-05, winning 3-2 on aggregate. But despite knocking Arsenal out of the competition twice as Barcelona manager, Guardiola never won against Arsenal in London. In 2011, his side lost 2-1 before winning 3-1 at the Nou Camp. The season before, Barcelona drew 2-2 before advancing to the semifinal stage with a 4-1 win.