BOSTON -- With the Boston Red Sox less than 24 hours removed from an embarrassing 21-2 defeat at the hands of the Los Angeles Angels, the bar wasn’t set particularly high for starter Sean O’Sullivan on Sunday.

Manager John Farrell said before the game that he would take four or five effective innings from the right-hander. And he was thrilled afterward when that was exactly what he received, as O’Sullivan shut out the Halos over his first five frames to lead the Sox to a much-needed 10-5 win and their first series victory in their past four attempts.

In all, the 28-year-old allowed just two runs on four hits in five-plus innings. Given the way the Red Sox have pitched of late, that was more than enough to warrant a standing ovation from the sellout crowd at Fenway as he walked off the mound.

“It was only five [innings] coming out in the sixth,” O’Sullivan said, admitting that the reaction surprised him. “That’s one of the highlights of my career, for sure.”

O’Sullivan’s performance was a highlight for the rest of the team as well. It’s been an all-too-common theme for the starters to put the offense in an early hole lately, which O’Sullivan was well aware of as he took the mound.

“I knew it was going to be important to put up some zeroes early to give our offense a chance to get on the board first,” he said. “Our defense back there is too good not to let them do their thing behind us, so I just tried to fill up the zone with strikes and get contact. Tried to give as much length as I could.”

O’Sullivan was aided early by the defense, particularly by center fielder Jackie Bradley Jr., who had two outfield assists within the first three innings of the game. The second one loomed especially large, as Bradley chased down a Yunel Escobar line drive to deep center with a leaping catch and fired a strike to second base to double off Jett Bandy, bailing his starter out of a two-on, one-out jam with the meat of the Angels’ order ahead.

“On the play I kind of broke in, tried to go back up,” Bradley said. “I had to readjust and head towards the gap. Got a good read on it, made a timely leap and made the play.”

Not long after, the Red Sox’s offense kicked into gear, scoring seven runs off Angels starter Matt Shoemaker and reliever Jose Alvarez in the bottom of the fifth, all of which came with two outs. Hanley Ramirez and Sandy Leon had the big hits in the frame, each connecting for a two-run double.

Ramirez had three hits on the day to run his average to .417 in his past 10 games, while Leon further improved his chances of remaining with the club when Ryan Hanigan is activated from the disabled list by raising his season average to .457 with two hits and a career-high three RBIs.

All things considered, it was exactly the kind of game the Red Sox -- “full of piss and vinegar” entering the day, according to Farrell -- needed after the way things went Saturday.

“The great thing about coming right back the next day is we turn the page and put it behind us,” Farrell said. “It was very good to see us go out and set the tone with Sully on the mound. We needed those five shutout innings to get on track offensively and we were able to respond to that.”

Needless to say, the boost O’Sullivan provided didn’t go unnoticed. With an off day on Thursday, the Red Sox appear poised to turn to the journeyman once again on Friday instead of Clay Buchholz, who was the primary perpetrator in Saturday’s blowout loss.

“We’re working through it, but he certainly hasn’t hurt his chances,” Farrell said of O’Sullivan. “[He gave us] exactly what we were looking for -- stabilize the game from the onset. He did that today.”

That’s more than Buchholz can say.