* Kroos, Mueller and Mandzukic give Bayern victory
* Arsenal's Podolski scores against his old club
* Arsene Wenger's side booed off at final whistle (Writes through, adds more quotes)
LONDON, Feb 19 (Reuters) - The Bayern Munich juggernaut rolled on with a 3-1 first-leg win over an Arsenal side lacking confidence and ill-equipped to stop the German giants seizing control of their Champions League last 16 tie on Tuesday.
The runaway Bundesliga leaders have been flattening everything in their path for most of this season while Arsenal have struggled to keep pace with the Premier League's big guns while suffering some humiliating domestic cup defeats.
The gulf in confidence and class was obvious as goals by Toni Kroos, Thomas Mueller and Mario Mandzukic earned Bayern their first ever win in London to make them overwhelming favourites to reach the last eight.
On this form, it will take a good side to stop four-times European champions Bayern returning to north London in May at Wembley to contest a third Champions League final in four seasons.
"Here in England it has been hard for Bayern in the past," coach Jupp Heynckes, who will make way for Pep Guardiola at the end of the season, told reporters.
"We've scored three goals in an away game, that's quite good. I think Arsenal allowed us quite a few things in their defence but we are in astonishing form at the moment and we can punish the smallest mistakes of opponents."
Oozing confidence after an 18-match unbeaten sequence which sees them 15 points clear at the top of the Bundesliga, Bayern had seized control of the match before the midway point of the first half with Kroos and Mueller both on target.
Arsenal did rally after the break with Lukas Podolski cashing in on a rare piece of generosity from the visitors but just when Arsene Wenger's side looked as though they might restore parity, Mandzukic put Bayern out of reach again.
"Let's not hide from the fact that it will be very difficult (to win the tie)," Wenger, who is under increasing pressure from fans and in the media, told reporters. "They haven't played in two finals in three years for no reason.
"We played against a side with no doubts, with everything positive, and that's not the case with us at the moment."
"We put in a good battle in the second half and looked like we could get it back to 2-2 but to go 3-1 was a big blow for the team and we could have conceded more."
Determined to make amends for a 1-0 defeat by second tier Blackburn Rovers in the FA Cup fifth round on Saturday, Wenger's side began positively with Santi Cazorla and Theo Walcott advancing deep into Bayern territory.
Their apparent confidence proved to be an illusion, however, once Bayern struck after seven minutes.
Mueller, a constant menace down the right flank, was allowed time to cross and his scuffed delivery wrong-footed Arsenal's defence and fell perfectly for Kroos to swivel and thump a first-time shot into the turf and past keeper Wojciech Szczesny.
Sensing Arsenal's unease, Bayern doubled their advantage after 21 minutes when Daniel Van Buyten's glancing header from a corner was blocked on the line by Szczesny but the ball popped up for Mueller to flick it into the unguarded net.
Bayern looked capable of putting the tie to bed before halftime and almost did so moments before the break when Mandzukic rose majestically to meet Philipp Lahm's cross but placed his powerful header agonisingly wide.
Arsenal's frustration resulted in first-half bookings for Bacary Sagna, Thomas Vermaelen and Mikel Arteta while Bayern's Bastian Schweinsteiger was yellow-carded for kicking the ball away and will be ruled out of the return leg in Bavaria.
Schweinsteiger's moment of ill-discipline would normally have been costly but his absence is unlikely to threaten his side's progress in the second leg.
Arsenal briefly rose to the challenge and 10 minutes into the second half, a corner from Arsenal midfielder Jack Wilshere found former Bayern forward Lukas Podolski unmarked and he gratefully nodded a bouncing ball past keeper Manuel Neuer.
It was the first goal conceded by Bayern this year and rattled the visitors as the home crowd sensed that maybe all was not lost amid memories of Arsenal's 2-2 draw with Barcelona in 2010 when they also trailed 2-0.
Arsenal substitute Olivier Giroud nearly equalised with his first touch after joining the fray with 20 minutes left but his sweetly-struck shot from Walcott's cross flew straight at Neuer.
The revival was cut short after 77 minutes when Bayern counter-attacked in devastating fashion and Lahm's skidding cross spun up and in off Bayern's Croatia striker Mandzukic.
Arsenal huffed and puffed looking for a reply but Bayern were better in every department and the home side were booed at the end, just like on Saturday, with their season now seemingly hinging on a scramble to finish in the Premier League top four. (Reporting by Martyn Herman; editing by Ken Ferris)