If the Red Sox wanted to give themselves any realistic shot at making the playoffs, they had to take care of business this weekend against the woeful Chicago White Sox.

They won the series, but Sunday they let perhaps the best opportunity to gain ground they’ll have slip away.

The Red Sox gave up five runs in the top of the ninth en route to a backbreaking 7-2 loss to the White Sox. All of those runs were charged to Zack Kelly, who allowed five hits and an intentional walk while recording just one out, and Boston’s offense collectively went 0 for 6 with runners in scoring position.

It’s only Chicago’s sixth win since the All-Star break, and with the loss Boston squandered an opportunity to move within three games of the Minnesota Twins in the American League Wild Card race.

If there was one encouraging sign this weekend that could bode well for the home stretch, it was the play of Trevor Story.

Activated on Saturday after missing five months with a fractured shoulder, Story has immediately made his presence felt defensively while contributing a little at the plate as well. Sunday he put forth a masterclass at shortstop, helping make two difficult double plays look easily while helping Richard Fitts enjoy a memorable afternoon in his MLB debut.

With Story backing him up, Fitts pitched into the sixth inning and probably would have left with the lead if not for a costly error by Triston Casas at first base. The 24-year-old, originally acquired in this past winter’s Alex Verdugo trade, wound up being charged with two runs (both unearned) on six hits and a walk with two strikeouts over 5.2 innings.

The first inning wasn’t exactly a glorious display of baserunning. The White Sox ran into an out when Luis Robert Jr. was picked off at first base after singling in his first at bat, and the Red Sox one-upped that by running into two outs in the bottom of the frame. Jarren Duran was out by a mile at home after he was sent on a double down the right field line by Wilyer Abreu, and Abreu was caught between second and third for the final out of the inning.

The Red Sox recorded a third out on the bases later when Story was caught stealing second in the third inning.

Boston took the lead in the second when Connor Wong hit a solo shot for his 13th home run of the season, but beyond that the Red Sox weren’t able to do much damage against White Sox starter Chris Flexen, who came into the game on a historic cold streak. The right-hander came into the game 2-14 with a 5.36 ERA, and since he last recorded a victory on May 8, his team hadn’t won any of his 21 starts since.

The offense squandered perhaps its best chance in the fifth, when Masataka Yoshida walked and Connor Wong singled to put two on with no outs. Both runners advanced into scoring position after Casas grounded out, but neither came home to score, with Flexen striking out Story and Enmanuel Valdez to end the threat.

That failure quickly proved costly when Casas let a line drive by Zach DeLoach go under his glove for a two-base error to start the sixth. DeLoach came around to score and tie the game two batters later on an RBI groundout by Andrew Benintendi, and Korey Lee followed with an RBI single to give Chicago a 2-1 lead.

Boston didn’t trail for long. Abreu tied the game with a solo home run with two outs in the sixth, a frozen rope that looked like a liner into the gap off the bat but wound up carrying 427 feet over the Red Sox bullpen.

Other than Wong and Abreu’s solo shots, however, the Red Sox couldn’t sustain any kind of momentum, and in the top of the ninth things went completely off the rails. Kelly allowed a leadoff single, got a strikeout and then let the next five men reach safely. Dominic Fletcher gave Chicago the lead with his go-ahead RBI double, and things just snowballed from there.

Nineteen games remain. Next up is the Baltimore Orioles, who come to Fenway Park seeking to solidify their own position amid a heated battle for the AL East championship with the New York Yankees.