- Lewandowski has now taken his season tally to 42 goals in all competitions
- It took only 12 minutes to score his first against Salzburg, from the penalty spot
- The third came from open play, running onto Müller's pass and then knocking a shot into the net
Whatever hope Salzburg had of overcoming Bayern Munich was extinguished by Robert Lewandowski scoring a hat trick in 11 minutes.
It was game over by the time Lewandowski's third hit the net in the 23rd minute on Tuesday to make it the quickest treble ever seen at the start of a Champions League match.
A second leg that started at 1-1 was tilted 4-1 in Bayern's favour by the striker's scoring masterclass. An 8-2 aggregate win to reach the quarterfinals was completed by further goals from Serge Gnabry, a double from Thomas Müller, and Leroy Sané. At least Salzburg avoided complete humiliation of not scoring with Maurits Kjaergaard netting for the Austrian team in Bavaria.
"That was a statement win," Bayern captain Manuel Neuer said. "I think we showed a different side of ourselves today and didn't concede as many chances on the break. We were also more stable in defense, which obviously gives us hope that things can continue in that vein."
Tuesday's other round of 16 game was far tighter with Liverpool relying on its 2-0 victory at Inter Milan to advance after losing 1-0 at Anfield.
It was three weeks ago when Bayern was reliant on a late equaliser from Kingsley Coman to avoid losing the first leg.
After failing to score — or even hit the target in Salzburg — Lewandowski has now taken his season tally to 42 goals in all competitions.
It took only 12 minutes to score his first against Salzburg, from the penalty spot after being brought down by Maximilian Wober. The defender fouled him again and Lewandowski converted his penalty again in the 21st.
The third came from open play, running onto Müller's pass and then knocking a shot past the advancing goalkeeper Philipp Köhn from the edge of the penalty area.
The previous quickest hat trick from the start of a Champions League match came in 24 minutes from Marco Simone for AC Milan against Rosenborg in 1996.
"Today it was an opponent on a different level," Salzburg defender Rasmus Kristensen said. "We had some chances but if you don't make them count, it is difficult. We gave everything but it wasn't enough. It had nothing to do with attitude, focus or the match plan. They simply have been better in all aspects — that's it."
Coman seized the ball off Mohamed Camara to set up Gnabry in the 31st to shoot under Köhn.
Müller scored nine minutes into the second half before Kjaergaard struck a superb left-footed consolation for the knockout phase newcomer. But Müller swept in his 52nd Champions League goal in the 83rd after exchanging passes with Lewandowski and Sané in the buildup.
The rout was completed with an assist from the striker who started it. Lewandowski back-heeled the ball for Sané to net the seventh in the 85th.
"Today we had the luck that was completely missing in Salzburg," Müller said. "We could have gone 1-0 down after five minutes. You're always a little dependent on situations like that, but overall we were better."
(Reported by AP)