SAN FRANCISCO — Luis Severino gave the Mets’ rotation a boost Tuesday night by pitching six innings, looking good in five of them.
The exception cost him and loomed even larger as this suddenly slumping Mets lineup was burrowing further underground against last year’s runner-up in the National League Cy Young award voting.
Logan Webb became the second starting pitcher in three days to pitch eight shutout innings against the Mets, who lost 5-1 to the Giants at Oracle Park.
The Mets, who lost their third straight, got blanked over eight innings by Tyler Glasnow on Sunday on their way to a shutout loss in Los Angeles and followed that with two runs Monday.
Webb allowed only six hits over 106 pitches before the Mets scratched for a run against Tyler Rogers in the ninth.
“[Webb] is one of those pitchers that has a lot of pitches that have a lot of movement, and they come at very different angles,” Starling Marte said through an interpreter. “Whenever he releases, they all look [like] strikes, so you really have to focus and really hope when you make a swing it’s a ball that is located where you can take advantage of it.”
Suddenly, a road trip that began with so much promise for the Mets — with two straight victories over the Dodgers — is in jeopardy of turning into a disappointment.
The Mets need a victory in Wednesday’s series finale to salvage a .500 trip.
Severino allowed three earned runs, all of them in the fifth inning. He surrendered five hits and struck out five without walking a batter.
The Mets still haven’t had a starter pitch into the seventh inning this season, but Severino’s six was welcomed after Sean Manaea, Jose Butto, Adrian Houser and Jose Quintana had fallen short of that mark over the previous four games.
The Giants jumped on Severino with four singles in the fifth. Michael Conforto’s bloop single to left leading off the inning gave the Giants their first base runner after Severino retired the first 12 batters.
Matt Chapman followed with a single, and with one out, Thairo Estrada singled in Conforto, advancing to second on the throw home.
Mike Yastrzemski’s ensuing single brought in two runs to place the Mets in a 3-0 hole.
“A couple of bloopers in there, but that’s part of the game,” Severino said. “I made great pitches and if I continue to do that out there things are going to go my way.”
Severino said he was well aware of the opposing pitcher and the need to limit damage.
“[Webb] is in control of the zone and really good at getting ground balls, that is why he can get really deep in the game,” Severino said. “I knew going into the game I was going to be out there competing and try to get that game to be a close game, a couple of runs, because I know how good he is.”
Omar Narvaez doubled with two outs in the third to snap an 0-for-16 drought, but Webb retired Brandon Nimmo to end the threat.
Webb had retired the first eight batters he faced, seven of them on grounders.
Marte singled leading off the fourth but refrained from attempting a steal of second.
That decision was magnified as Francisco Lindor hit into a double play.
Jeff McNeil reached on a two-out infield single in the fifth before Webb struck out Joey Wendle, who started at second base to give the Mets an extra left-handed bat in the lineup with Harrison Bader on the bench.
In the inning, Conforto robbed DJ Stewart of a bloop single to left with a diving catch.
In the sixth, Marte stroked a two-out double before Webb struck out Lindor to end the threat.
Webb allowed a leadoff single to Alonso in the seventh before retiring the next three batters to keep his shutout intact.
Drew Smith entered for the seventh and surrendered a leadoff triple to Estrada and an RBI single to Yastrzemski that increased the Mets’ deficit to 4-0.
LaMonte Wade Jr.’s double off Lindor’s glove brought in the Giants’ fifth run. Smith had allowed only one earned run in his previous nine appearances.
“We’ve been facing some good arms,” manager Carlos Mendoza said. “But we’ll be ready for [Wednesday
