The Germany international feels that the Ligue 1 champion played into its hands by pushing high up the pitch after the interval, but warned the tie is not over yet.
Bayern recorded a 2-0 victory at the Stade Velodrome, and Lahm feels that OM played right into FCB's hands as they allowed the Germans plenty of space after the interval.
"We knew Marseille are a physically robust team who'd be sure to stand up to us. But we stood up to them well in return and scored a very, very important goal just before half-time. That played into our hands, as we saw in the second half," Lahm stated to the official Bayern website.
"Whenever we find a bit of space in attack, we always create good goalscoring chances. It worked out very well.
"Winning 2–0 away from home is an outstanding result, but it's still the quarterfinals and you always have to watch yourself. We're not through yet."
Bayern and Marseille meet again on April 3 at the Allianz Arena.
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