BOSTON — Alfredo Aceves lost his winning streak and very likely his spot in Boston’s rotation, all in one terrible night.

Aceves gave up eight runs in five-plus innings and lost for the first time in more than two years Tuesday night as the Red Sox dropped their third straight, 10-7 to the Chicago White Sox.

And while Aceves (2-1) was struggling in Boston, right-hander John Lackey was making a solid rehab start for Triple-A Pawtucket.

“It was a bad day for me,” said Aceves, who had his worst outing since joining the rotation when Lackey was sidelined with a strained right elbow.

After a pair of strong starts, giving up one run in each over a combined 11 innings, Aceves gave up four in the second, and one in the third and fourth before he was chased during a four-run sixth.

“I don’t think he executed like he has been the last couple of outings,” Red Sox Manager Terry Francona said. “Saying that, there were some balls that found some holes, the two walks.”

Asked for a report on Lackey, Francona said: “They actually had to keep him out there a little longer because he was so good.”

Francona went on to say Lackey will start Sunday.

The problem was, Aceves didn’t seem to know.

“Every five days,” Aceves said when asked what’s next for him.

When asked what he would do if he was asked to go to the bullpen, Aceves said: “I’ve been saying since spring training, I’m a pitcher.”

Lackey gave up one run in 52/3 innings, striking out four in a 63-pitch outing.

Alexei Ramirez tied his career high with four hits, and Philip Humber stymied Boston for seven innings.

It was Chicago’s sixth straight win at Fenway Park, its longest streak since the “Go Go” Sox era of 1958-59.

Humber (4-3) scattered six hits in the first seven innings before giving up three more in the eighth as Boston cut it to 10-5. Humber was charged with four runs, walking one and striking out five in 72/3 innings — the first time in seven starts he’s yielded more than three runs.

Chris Sale came on in the ninth after Boston cut the deficit to 10-7 and struck out Adrian Gonzalez looking on three pitches to earn his second save.

Aceves allowed six earned runs on eight hits and three walks, striking out one. He had won 12 straight decisions for the Yanks and Red Sox in what had been the longest active streak since CC Sabathia in 2008.

But the White Sox scored four in the second, including a two-run single by Ramirez. He also singled and scored when Chicago added four in the sixth to chase Aceves and make it 10-1.

Despite their three-game losing streak, the Red Sox are 19-10 in May — the best record in the American League over the month. Gonzalez had 42 hits and 31 RBI in the month, the first Red Sox player to top 40 and 30 in May, respectively, since Jim Rice in his AL MVP year of 1978.