Barca restore Liga lead in Girona romp
After second-placed Real Madrid pulled level on points with them on Saturday by beating Leganes, Hansi Flick's side restored their advantage at the Olympic Stadium.
Lewandowski responded to Madrid striker Kylian Mbappe's double with one of his own to stay three goals ahead in the race for Spain's golden boot.
Barcelona, unbeaten this year in 20 matches, took the lead through a Ladislav Krejci own goal near the end of the first half.
Arnaut Danjuma pulled Girona level but Lewandowski netted twice and Ferran Torres finished off the rout.
Girona beat Barcelona twice last season but have struggled to hit those heights again and sit 13th.
"We played with patience, we had a plan and if we play with that plan we can always score a lot of goals and win the game," veteran striker Lewandowski told DAZN.
The 36-year-old said he had the legs to keep playing for seasons to come.
"I know a lot of people are talking abut my age but... I want to play more years at the top level," said the Poland international.
"I feel very good physically, I think looking at the stats there's no difference now to a few years ago."
Flick rotated some of his usual suspects with the Copa del Rey semi-final clash against Atletico Madrid in mind.
Barca were below their free-flowing best in the first half despite dominating, occasionally threatening through the dynamic running of teenage star Lamine Yamal and frantic energy of Fermin Lopez.
Paulo Gazzaniga saved well from Lopez on the counter-attack after Viktor Tsygankov blazed over Girona's first decent opportunity.
Gazzaniga saved well from Lewandowski and then Yamal, who also fired over.
Barcelona wanted a penalty when Fermin was brought down by Yaser Asprilla on the edge of the box and a free-kick was given.
A VAR review showed the contact was inside the area but the referee decided Lopez fouled Asprilla as they came together, much to Barcelona's chagrin.
Breakthrough
Gazzaniga produced a sensational save with his fingertips to push out a Ronald Araujo header but Barca found a way through before half-time.
Yamal's dangerous free-kick aimed at Eric Garcia was deflected into his own net by Krejci at the near post.
Girona had produced very little of note in the first half but were back level eight minutes into the second through Danjuma.
Daley Blind played the Dutch striker through and he beat Wojciech Szczesny with a clinical low finish.
However Barcelona were swiftly back in front as La Liga's top goalscorer Lewandowski notched his 24th of the campaign.
Lopez nodded the ball across the six-yard box and Lewandowski contorted his body to reach it and flick it between Gazzaniga's legs.
The forward secured Barcelona's victory with his 25th, slotting home after substitute Frenkie de Jong pushed forward into space and fed him.
There was time for Torres to add a fourth after Gerard Martin found him and the brilliant Yamal to bend a strike against the crossbar.
This was remarkably the 20th time this season Flick's side have scored four goals or more from 45 games, with a potential treble in their sights.
"In the first half we had the game under control but lacked the final ball, but in the second half we played more attacking, made more chances and scored some goals, that's the most important thing," added Lewandowski.