Lewandowski's brace yesterday came in a crazy first half where Bayern rattled five goals past a demoralised Porto side, who had come into the game leading 3-1 after the first leg and with real hopes of reaching their first semi-final since they won the trophy in 2004.
The game ended 6-1 and a 7-4 aggregate victory for Bayern and extended their coach Pep Guardiola's remarkable record in the competition where in six campaigns he has never failed to reach the last four.
For his opposite number Julen Lopetegui it was a devastating evening.
Neymar also scored his double in the first half for Guardiola's former side Barcelona -- whom he guided to two Champions League trophies in his spell there -- as they eased to a 2-0 win on the night and a 5-1 aggregate win over French champions Paris Saint Germain.
"I am very happy with the season I am having and we need to continue like this to achieve our objectives. We need to keep going and get to the final," said Neymar, who took his tally to 30 goals for the season.
While Barcelona, who have won 23 and drawn one of their last 25 games, reached their seventh semi-final in eight seasons, for PSG it was their third successive exit at this stage.