SAN FRANCISCO – David Peterson’s pattern in allowing runs in his four starts before Saturday was good, bad, good, bad.

The pattern is now broken – a term the Mets hope also doesn’t apply to the pitcher.

The left-hander had a second straight turbulent outing, getting jumped in the first inning and never recovering in the Mets’ 7-4 loss to the Giants at Oracle Park.

The loss was the Mets’ second in nine games on this West Coast trip.

Over five innings, Peterson allowed seven earned runs on seven hits with eight strikeouts and one walk.

It ranked as maybe the Mets’ worst starting pitching performance of the season, a day after they received their best: Joey Lucchesi delivered seven shutout innings for the win in his first major league appearance in almost two years.

On Tuesday, Peterson allowed six earned runs over six innings against the Dodgers.

The difference that night was the Mets’ bats saved him by producing eight runs, allowing him to escape with a win.

On this day the cavalry was relatively quiet against Logan Webb and the Giants bullpen.

The Mets had scored nine and seven runs in winning the first two games of this series.

Given the state of their rotation – Justin Verlander, Carlos Carrasco and Jose Quintana are on the injured list and Max Scherzer won’t return from a 10-game suspension until May 1 – the Mets have little choice but to stick with Peterson and hope he regains the form he showed last season when he was a dependable fill in.

Peterson had eight hard-hit balls against him in this latest start, according to Statcast.

Peterson got buried early, surrendering a three-run homer in the first inning to Brandon Crawford that gave the Giants a 4-0 lead.

Thairo Estrada reached on an infield hit and Michael Conforto singled before Wilmer Flores walked to load the bases.

David Villar’s sacrifice fly brought in a run and Crawford followed with a no-doubt homer to right field.

Daniel Vogelbach’s two-out RBI double in the second got a run back, but the Giants jumped on Peterson again in the second to score twice.

Darin Ruf delivered an RBI single for the Giants’ third hit of the inning and Michael Conforto’s fielder’s choice brought in the other run.

Brandon Nimmo’s sizzling road trip continued with a homer in the third inning that sliced the Giants’ lead to 6-2.

The blast was the second in four games for Nimmo, who entered play with a .525/.568/.725 slash line over his previous nine games.

Peterson’s troubles continued in the fifth with Wilmer Flores’ leadoff homer against him.

The blast was the fifth allowed by Peterson over his last two starts.

Flores jumped on a four-seam fastball and cleared the left-field fence for his third homer of the season.

Starling Marte brought in the Mets’ third run with a single in the eighth.

Marte returned to the lineup after missing the previous two games with a sore neck.

Brett Baty’s single in the ninth produced the game’s final run.