ROBERT LEWANDOWSKI scored two as Bayern Munich eased to a 3-0 win in Barcelona as the Champions League group stage started Tuesday.

Meanwhile, Manchester United was upset in a late 2-1 loss at Swiss champion Young Boys, and Romelu Lukaku’s second-half header gave defending champion Chelsea a 1-0 win over Zenit St. Petersburg.

Bayern hammered Barcelona 8-2 in the teams’ last meeting in the quarterfinals in 2020, and the home side seemed fearful of another rout after its summer of upheaval saw the departures of Lionel Messi and Antoine Griezmann.

Bayern might have won by more but will be happy with 3-0 after another dominant performance.

Thomas Muller scored with a deflected shot in the 33rd minute to ensure Bayern scored for the 23rd consecutive Champions League game, a club record.

The visitors had been pushing harder and it seemed only a matter of time before the breakthrough would come. Muller’s shot struck Eric Garcia’s back to deceive Barcelona goalkeeper Marc-Andre ter Stegen.

Lewandowski got the second in the 56th on a rebound after 18-year-old Jamal Musiala’s effort struck the post.

It stretched Lewandowski’s scoring run to 18 consecutive games across all competitions for Bayern. But that didn’t mean he had enough.

The Poland star scored his second goal in the 85th, again after a teammate — Serge Gnabry — hit the post, though there was plenty for Lewandowski to do as he slotted the ball past a host of defenders.

Cristiano Ronaldo struck early in his first Champions League game for United since losing the 2009 final, but American forward Jordan Pefok had the last laugh in a dramatic 2-1 win in Bern.

Ronaldo didn’t take long to make his mark in his record-equaling 177th appearance in the competition — squeezing his shot under goalkeeper David von Ballmoos in the 13th minute after a brilliant cross from Bruno Fernandes.

Only Ronaldo’s former Real Madrid teammate Iker Casillas has as many Champions League appearances.

(SD-Agencies)