After a lost year due to COVID-related heart problems, Eduardo Rodriguez is back atop the Red Sox rotation.

The Boston left-hander struck out eight Mariners in six innings to beat Seattle 5-3 on Sunday and remain unbeaten on the season. The Red Sox had lost three of four since his previous outing.

"That's what aces do," Red Sox manager Alex Cora said. "They put their team on their back and they carry us to a 'W.'"

Rodriguez (4-0) gave up six hits - five of them doubles - and no walks to help the Red Sox earn their major league-leading 11th comeback victory of the season. He won 19 games in 2019 and then missed all of last season with inflammation in his heart muscles as a result of COVID-19.

Asked if he felt like he was all the way back, he said, "I'm all the way back already. From the first start of the season."

"Today was just one of those days you don't feel too much power on your fastball," he said. "But the command was there, and it was good to have it."

Rodriguez has lasted at least five innings in 32 straight starts dating to May of 2019. The Red Sox have won his last eight outings and the team is 49-12 in his starts since the beginning of the 2018 season.

"I don't call myself an ace. I just go and pitch all the time," he said when told that Cora had named him the staff leader. "For me I don't think I am. If he thinks it, I appreciate it."

J.D. Martinez had two more doubles, giving him 10 for the year - the most in baseball. He also ended the game tops in hits, 30, tied with Xander Bogaerts, who had a double of his own to help the Red Sox split the four-game series and improve to .500 at Fenway Park.

"We believe that you have to dominate at home," Cora said as the team ended a 10-game homestand before heading to New York and Texas for a six-game road trip. "But when you aren't playing well for 10 days, 5-5 we'll take that."

Seattle starter Nick Margevicius (0-2) got just one out while allowing four runs in the first inning. He faced seven batters and walked four of them -- two with the bases loaded -- while also allowing two hits.

Rodriguez had trouble in the first, when he allowed back-to-back groundball doubles through the left side of a shifted infield to Mitch Haniger and Ty France to lead off the game. And a little more in the fifth, when Sam Haggerty led off with an infield single, Tom Murphy followed with a chopper down the third-base line for a double and J.P. Crawford grounded one down the first-base line for another.

"He understands that ground balls can turn into doubles. ... He just kept throwing strikes," Cora said. "That's what aces do. Not a perfect day, just go out there and give them seven innings and flip to the bullpen."

Adam Ottavino pitched a scoreless eighth and Matt Barnes pitched a perfect ninth for his fourth save.

MARGE-VICIOUS

After taking the mound with a 1-0 lead, thanks to back-to-back doubles by Mitch Haniger and Ty France to lead off the game, Margevicius opened the game single-walk-walk-(mound visit)-strikeout-RBI single-walk-walk. The Seattle lefty threw just 13 of his 32 pitches for strikes.

Drew Steckenrider replaced him and hit Christian Arroyo, scoring another run, before Bobby Dalbec grounded into an inning-ending double play. The Red Sox made it 5-1 in the second on two walks and Bogaerts' RBI double.

TRAINER'S ROOM

Red Sox: CF Alex Verdugo was scratched from the lineup about an hour before the first pitch because of the cold and rainy conditions. He had a hamstring cramp on Saturday but remained in that game. ... Arroyo got some attention from the training staff stayed in. Cora said he was getting X-Rays after the game.

UP NEXT

Seattle: At Houston, where LHP Justus Sheffield (1-1) will face Astros RHP Jose Urquidy (0-2).

Boston: Off Monday, with RHP Garrett Richards (0-2) facing Mets LHP David Peterson (1-2) in New York on Tuesday.