Cuddyer hit a tiebreaking single in the seventh inning and the NL East leaders stopped their five-game home skid, averting a sweep by beating the Boston Red Sox 5-4 Sunday.
The 36-year-old Cuddyer kept up his three-week surge since coming off the disabled list, going 3 for 3 with a walk. He's hit .375 after being sidelined by a bruised knee.
"It definitely was a factor. But it wasn't the reason I was struggling or whatever the case was," he said.
"And it's not the reason why I've gotten some hits the last few days. But it's part of it, there's no question about that," he added. "It feels good. Able to plant on it. Stronger."
Cuddyer didn't make much of an impact at the start of the season with his new team. Now, the 2013 NL batting champion is a key contributor.
"With his knee feeling better, he's swinging the bat great. And as we head down the last month, he's going to be important," manager Terry Collins said.
"He's an outstanding player and he's a pro. That's why we got him here," he added. "We brought him in here to be that kind of a player."
Cuddyer's go-ahead hit came after Daniel Murphy stole second base with two outs -- "sneak-attack mode," Cuddyer said.
The Mets held their 5 1/2-game division lead over Washington.
"The Mets, with that pitching staff, man, they're not too far from walking into the money," Ortiz said.
Tyler Clippard (2-0) got four outs for the win. Jeurys Familia worked around two singles to begin the ninth, striking out Mookie Betts with runners at the corners to close out his 35th save in 40 chances.
Before the game, the Mets completed their trade to get reliever Addison Reed from Arizona. The Mets hope Reed can fill the seventh-inning role and give their tired bullpen a break.
It was 4-all when Robbie Ross Jr. (0-2) walked David Wright with one out in the seventh and Murphy grounded into a force play. Heath Hembree relieved and, after Murphy stole on the first pitch, Cuddyer singled through the left side.
Boston scored twice in the seventh to tie it at 4. Pinch-hitter Jackie Bradley Jr. hit an RBI double with two outs that finished Syndergaard. Hansel Robles relieved and, after Bradley stole third without a throw, Betts wound up with an odd, tying triple.
Betts hit a high fly that fell down the left field line far in front of Cuddyer as Wright and shortstop Ruben Tejada gave chase. Betts saw no one covering third, and easily beat Wright to the bag.
Ortiz hit his 28th homer, a two-run shot in the sixth that put Boston ahead 2-1. Syndergaard singled home Cuddyer in the second against Wade Miley.
Red Sox: Interim manager Torey Lovullo said there's a "strong possibility" Hanley Ramirez will play first base later this season. The infielder-turned-outfielder has been working out at the new position, but is currently nursing a sore shoulder. ... 2B Dustin Pedroia (hamstring) will see a doctor in Boston on Monday as he progresses. ... C Ryan Hanigan, scratched Saturday with a calf problem, didn't start.
Mets: Wright returned to the lineup after getting a day of rest. He recently came back after spending more than four months on the disabled list, and the Mets don't want to overwork him.
Mets hitting coach Kevin Long was ejected by plate umpire Joe West in the third for arguing after Curtis Granderson was called out on strikes.
To make roster room for Reed, the Mets optioned RHP Logan Verrett to Triple-A Las Vegas.
Red Sox: LHP Eduardo Rodriguez (7-5, 4.39 ERA) pitches the opener of a three-game series against the Yankees at Fenway Park. He's 1-1 against New York this season.
Mets: RHP Bartolo Colon (11-11, 4.65) starts the opener of a three-game set vs. the Phillies. He pitched seven shutout innings at Philadelphia last week. On Saturday, the 42-year-old made his first relief appearance since 2011, throwing one inning to spare the bullpen.
Fantasy baseball pitcher rankings, lineup advice for Monday's MLB games
Everything you need to know to place your MLB bets and set your fantasy baseball lineups for Monday, October 3.
Munetaka Murakami hits 56th home run to move into second place on Japan's single-season list
Japanese slugger Munetaka Murakami, playing for the Tokyo-based Yakult Swallows, hit his 56th home run of the season on Monday, pushing him alone into second place on the single-season list.
Fantasy baseball forecaster: Team hitting ratings
Stay ahead of the game and optimize your fantasy baseball hitters with our forecaster, which provides a rolling 10-day outlook of every team's hitting matchups as well as the potential for stolen bases.
Fantasy baseball forecaster: Pitcher projections for the next 10 days
Keep up to date on who is pitching -- and how well they're expected to do -- with our forecaster, which provides a rolling 10-day outlook of every team's probable starting pitchers with game score projections.
Jeremy Pena's single extends Astros' lead
Jeremy Pena's single extends Houston Astros's lead
Cardinals Pujols hits 702nd HR, honored by fans
- Albert Pujols hit his 702nd career home run and tied Babe Ruth for second on the all-time RBI on Sunday, but the Pittsburgh Pirates took the game from the St. Louis Cardinals 7-5.