It was not a very happy 25th birthday for Brayan Bello on Friday night at Busch Stadium.

Making his second start since returning from the injured list at the start of the week, Bello served up three of four Cardinals homers and didn’t get out of the fifth inning as the Red Sox dropped the opener of a three-game set, 10-6. The loss dropped Boston to 22-23, marking the first time the club is under .500 since the third day of the season (March 30 at 1-2). The Red Sox have lost seven of their last 10 games and are 5-10 in May.

Brayan Bello was tagged for three homers Friday night in St. Louis

Playing in St. Louis for the first time since May 2017, the Red Sox didn’t take long to fall behind Friday night. After squandering a scoring chance in the first inning when Rafael Devers grounded into an inning-ending double play, Boston dug itself a two-run hole when Bello allowed a leadoff double to Brendan Donovan and a two-run homer to Lars Nootbaar in the bottom of the first. In an unusual development, the bottom of the lineup struck back in the top of the second when Tyler O’Neill singled, Dominic Smith doubled and rare starter David Hamilton drove them in with a two-out, two-run triple to tie the game. The Sox weren’t even for long, though.

With one out in the second, Nolan Gorman crushed his sixth homer of the year to left-center. The Red Sox answered minutes later when Devers, who has been red-hot in May, blasted a 443-foot solo shot — his seventh of the year and third in as many games — to tie it, 3-3. The Cardinals got the lead back when Alec Burleson led off the fourth with a solo shot off Bello, matching a career high in homers allowed for the righty, who turned 25 on Friday.

Boston did little offensively against the veteran Gibson from there and St. Louis added an insurance run off Bello in the fifth when Donovan laced a one-out double and came around to score on a Paul Goldschmidt RBI single. That ended Bello’s night; he went just 4 ⅔ innings, allowing five runs on seven hits while recording four strikeouts. Bello’s ERA rose to 3.96 in his second start since returning from the injured list.

Two of the three homers Bello allowed — to both Nootbaar and Burleson — came on his changeup, which got just three whiffs for Bello on 28 pitches.

“The changeup wasn’t good today so it was tough for him to get some swings and misses,” said manager Alex Cora. “He felt like the slider was better than the changeup. He ran through it and gave us (4 ⅔). But if you look at the outing, the damage was done on the changeup and he felt like he never had the feel for it tonight.

“Not having his best pitch put him in a bad spot.”

From there, the teams exchanged runs late. St. Louis tacked on some insurance in the bottom of the sixth when Masyn Winn took lefty reliever Cam Booser deep with a two-run shot that made it 7-3. Boston got within two runs again a half-inning later when Jarren Duran (RBI groundout) and Connor Wong (RBI double) drove in runs off lefty JoJo Romero to bring the score to 7-5. They weren’t that close for long as righty Chase Anderson came in and allowed three singles and a walk — including RBI knocks by Burleson and Iván Herrera — as St. Louis once again stretched the lead to four in the seventh. Two walks and a Nolan Arenado RBI single in the eighth made it a 10-5 game as Anderson was tagged with three runs in total. Rob Refsnyder reached on an error and plated a run on a Devers RBI groundout in the ninth to cut the deficit to four.

For the Red Sox, Duran (1-for-3, 2 BB) reached base three times, and Wong (4-for-5, double) had four hits as his average rose to .362. In his return to St. Louis, where he played the first 477 games of his big league career from 2018-23, Tyler O’Neill went 1-for-4 with a run.

Crawford gets nod on Saturday night

The Sox and Cardinals will be back at it Saturday night with first pitch scheduled for an hour earlier (7:15 p.m. ET / 6:15 p.m. CT). Boston will send righty Kutter Crawford (2-2, 2.24 ERA) to the mound against struggling Cardinals righty Miles Mikolas (3-5, 6.19 ERA) in the second game of a three-game series.