SAN DIEGO — In a 6-2 loss to the Padres on Sunday, the Red Sox received a reminder: Sound, solid starting pitching — so critical to their midsummer resurgence — can be precarious.
Brayan Bello grinded through his worst start in two months, allowing five runs in 5⅔ innings. A day prior, Lucas Giolito walked four consecutive batters with two outs in the fifth inning of a 5-4 loss — a rare-of-late poor and short outing.
One bad day each hardly negates their recent good work, which has helped propel the Sox into playoff position heading into the final quarter of the season. But it did lead to the team dropping consecutive games for the first time since July 21-22 in Philadelphia — and highlight the importance of Bello and Giolito through September and beyond.
“Every time I face them, I feel mentally strong,” Bello said through an interpreter regarding pitching against the playoff-positioned Padres, Dodgers, and Cubs, all of whom he has seen in the past month. “Those are very good teams that we might face in the World Series. I love facing playoff-caliber teams and today was no exception.”
Beginning in early June, Giolito rediscovered his early 2020s form and Bello seemed to take a significant step forward. They combined for a 2.25 ERA and averaged 6.25 innings per game over the two months entering the weekend. The Red Sox went 14-7 in games they pitched. Together, Giolito and Bello stabilized — and then some — a rotation that lacked sure things behind ace Garrett Crochet, turning it from a motley crew to a group that threatened to be quietly formidable in a short playoff series.
By not bringing in a high-caliber starter prior to the trade deadline, Red Sox decision-makers were making a bet: Giolito and Bello could continue to do what was needed in the Nos. 2 and 3 rotation spots.
“Bello has been great,” said Alex Bregman (0 for 3, walk). “He’s not trying to punch everybody out. I think he was a little bit, early in the year, trying to do that. The maturity has been on full display.”
Manager Alex Cora said: “Every five days, regardless of the opponent, this guy can give us six innings.”
Cora credited Bello with pitching “a lot better than what the line [in the box score] is going to say,” citing soft contact on some key hits for San Diego (66-52).
Bello’s trouble: finishing innings. All of the Padres’ runs came with two outs.
In the sixth, he retired two of the first three batters. Then he threw 15 pitches and allowed two stolen bases, Xander Bogaerts’s RBI single, and two walks without finding that final out.
Cora called on Chris Murphy, a University of San Diego product making his second appearance in the series. Murphy walked Jake Cronenworth to force in Bello’s last run.
Bello’s first faltering came with two outs in the third, opening the door for a San Diego rally.
No. 9 hitter Freddy Fermin singled to give the Padres their first base runner. Then Bello hit Fernando Tatis Jr. with a pitch.
When Bello left an 0-2 four-seam fastball over the middle of the plate, Luis Arraez cracked it to left-center field, where it found grass for a two-run double. Center fielder Jarren Duran took a funky route to the ball, which wound up behind him and rolled to the wall.
The Padres’ Dylan Cease, a free agent to be, contributed one of his better outings in an uneven season: two runs in six-plus innings, petering out late. He struck out seven and walked two.
“We know the velocity and the spin rate of the fastball, but the slider was the game-changer,” Cora said. “We put some good at-bats later on, but early in the game, he was dominant.”
Of the Sox’ four hits off Cease, two were fluky. Wilyer Abreu’s popup to shallow left-center fell between shortstop Bogaerts and left fielder Ramón Laureano. And Romy Gonzalez singled on a slow chopper toward third base. Neither advanced past first.
Roman Anthony nabbed the Sox’ first firmly struck hit in the sixth, when he scorched a line drive to center field for a single. But two pitches later, Bregman rolled a double-play grounder to shortstop to end the inning.
The Red Sox (65-54) finally broke through in the seventh, when Cease walked Duran and Trevor Story singled, triggering his exit. Both went on to score when Bogaerts booted a would-be double-play grounder.
The Sox had the bases loaded with no outs in that inning, the potential go-ahead run at the plate three times. But Ceddanne Rafaela, Abraham Toro, and Anthony struck out.
“We put a good inning together there,” Bregman said, “and just didn’t finish it off.”
Tim Healey can be reached at timothy.healey@globe.com. Follow him @timbhealey.