NEW YORK -- A lot happened within the New York Mets' universe in the 20-plus hours between the end of Monday's game and the start of Tuesday's. But the Mets managed to maintain a sense of routine on the diamond, where they picked up Tuesday where they left off Monday.

Neil Walker's two-run triple keyed a four-run first inning for the Mets, who received six strong innings from right-hander Zack Wheeler on their way to a 6-1 win over the reeling San Francisco Giants at Citi Field.

Walker had the walk-off RBI single Monday night, when the Mets edged the Giants 4-3.

"There's been a lot of action around here," Mets manager Terry Collins said. "To get off, jump out to a big start like that I think that kind of let everybody have a deep breath and really just concentrate on the game."

The Mets took the field Tuesday about four hours after one-time ace right-hander Matt Harvey apologized to the team for the actions that earned him a three-day suspension and cost him his start against the Miami Marlins on Sunday. Newsday reported Harvey, who told reporters he was out late Friday night and golfed Saturday morning before not reporting to Citi Field for that night's game, was near tears as he spoke to teammates.

It was the second known tardiness issue involving Harvey, who missed a workout prior to the 2015 National League Division Series.

"I think he knows he's got people in his corner, no matter what their title is, that are going to help him try to go down the right path, do the right things," Collins said before the game.

Collins' voice then seemed to quiver when he said Harvey got a text from ex-teammate Bartolo Colon.

"It's pretty special that these guys are all there for him," Collins said. "So hopefully Matt gets it."

The Mets (16-16) have maintained their recent winning ways despite the distractions generated by Harvey. New York has won eight of its last 11, including three of four games since Saturday. The only loss came Sunday, when Adam Wilk was recalled from Triple-A Las Vegas to replace Harvey and gave up six runs (five earned) over 3 2/3 innings in a 7-0 loss to the Marlins.

With the recent surge, the Mets are at .500 for the first time since April 20.

"We came together as a group today," Walker said. "We hope the situation with Matt is completely behind us. Situations like this will make good teams stronger, so hopefully that's the case."

Jose Reyes (single) and Rene Rivera (double) added RBI hits later in the first for the Mets. T.J. Rivera delivered an RBI double in the second and Michael Conforto led off the seventh with a homer.

T.J. Rivera had three hits while Conforto, Rene Rivera and Wilmer Flores each had two hits.

Wheeler thrived with the unusual run support -- the Mets scored just 14 runs with him on the mound in his first five starts -- and allowed one run on two hits and four walks while striking out four in lasting six innings for just the second time in six starts this season.

"I felt the best that I have all season so far today," said Wheeler, who missed the previous two seasons while recovering from Tommy John surgery. "I would like to go a little bit deeper."

Four Mets pitchers combined to allow no hits over the final three innings.

Buster Posey homered in the fourth for the Giants (11-23), who have lost five straight and eight of 10.

"Got to stay behind them and keep thinking that you're going to come out of this," Giants manager Bruce Bochy said. "It's been a while, and we're just sputtering here."

Losing pitcher Jeff Samardzija recorded the only other hit for San Francisco with a third-inning single.

"With the way we're hitting, it's hard to give up four in the first inning," Bochy said. "You keep fighting and keep grinding. But two hits, that's not going to work."

Samardzija (0-5) managed to last seven innings despite giving up the six runs on 10 hits and no walks while striking out nine.

NOTES: To make room for RHP Matt Harvey on the 25-man roster, the Mets optioned LHP Josh Smoker to Triple-A Las Vegas. ... The Giants placed RHP Mark Melancon on the 10-day disabled list, retroactive to Saturday, with a mild right pronator strain. The team will announce a corresponding move Wednesday.