Run support continued to be lacking for Pirates pitcher Bubba Chandler on Friday night.

Against the Toronto Blue Jays, the hard-throwing rookie didn’t get any help from his defense, either.

Two errors contributed to a pair of unearned runs in a three-run third inning that sent the Pirates to a 6-2 loss at Rogers Centre.

The miscues — the Pirates had three in the game — took the shine off perhaps Chandler’s most impressive start of the season.

Chandler had a career-high 11 strikeouts — four more than his previous best — but it couldn’t keep him from losing his fifth consecutive decision. Chandler (1-6) hasn’t won a start since April 17.

“I thought that was one of the best, if not the best, start that he’s had,” manager Don Kelly said on the SportsNet Pittsburgh postgame show. “We didn’t play really good defense.”

Chandler became the 10th Pirates rookie to record 11-plus strikeouts in a game since 1901.

In the past six starts, however, the Pirates have generated just seven runs while he has been in the game. They had just one against the Blue Jays while Chandler was around.

The latest defeat came after Chandler gave up just two hits and one earned run in five innings. Two of the three runs the Blue Jays scored in the third were unearned courtesy of errors by catcher Endy Rodriguez and first baseman Spencer Horwitz.

“It could have gone completely off the rails,” Kelly said. “But for him to settle down and get as many strikeouts and whiffs that he did, I was really impressed with him.”

Chandler’s previous season high in strikeouts was six, which he accomplished twice. That was one strikeout short of his career high established last season.

“Overall it was a good outing,” Chandler said. “A good step in the right direction.”

From the start, Chandler was overpowering. He struck out three in the first and struck out the side in order in the fourth. After issuing a one-out walk in the fifth, Chandler ended his start with back-to-back strikeouts.

He departed after throwing 99 pitches, 63 of which were strikes.

“The thing that was most encouraging to me was his composure, his presence on the mound,” Kelly said. “He was able to stay in attack mode and work through things.”

Trailing 3-1 in the eighth, the Pirates got the first two runners aboard on Brandon Lowe’s walk and Nick Gonzales’ single against reliever Mason Fluharty.

Louis Varland replaced Fluharty, and Bryan Reynolds was summoned from the bench to pinch-hit. A wild pitch advanced both runners into scoring position, and Reynolds’ grounder on a 3-2 pitch scored Lowe to pull the Pirates within a run.

Varland struck out Konnor Griffin on three pitches and got Jhostynxon Garcia to ground out to short. He retired the side in order in the ninth for his seventh save.

The Pirates were 0 for 9 with runners in scoring position.

The Blue Jays added three runs in the eighth against Dennis Santana, with George Springer’s two-run double breaking it open.

The Pirates committed their second and third errors of the game in the third inning, and this contributed to Chandler needing 30 pitches to get three outs.

“It was a good learning step of what we need to feel and what we need to do when big-time situations come up,” Chandler said.

Springer began by reaching on catcher interference. Vladimir Guerrero Jr. followed with a soft single to center, and that gave Springer enough time to reach third ahead of the throw.

Daulton Varsho hit a grounder to Horwitz at first base. Horwitz, whose sacrifice fly in the first provided the Pirates with a 1-0 lead, had Springer caught between third and home. But rather than make Springer commit in either direction, Horwitz threw immediately to third, and his high throw sailed into foul territory.

The throwing error brought Springer home and gave the Blue Jays runners on second and third with the Pirates still searching for the first out of the inning. It was Horwitz’s first error of the season.

“Anytime a ball is hit, we have to make sure we get one out,” Kelly said. “He’s been so good for us at first base. He’s playing at a Gold Glove level over there, and it was a blip on the radar for him.”

After getting a strikeout, Chandler threw a hanging curveball to Yohendrick Pinango, who lined it sharply to right for a two-run double and 3-1 lead.

“The game was in my hands, and I let it slip away,” Chandler said.

Blue Jays starter Kevin Gausman (4-3) gave up one run on six hits in 623 innings for the win. He struck out eight, walked one and lowered his ERA to 3.27.

The Pirates took an early lead when Lowe singled with one out in the first, Gonzalez doubled off the left-field wall, and Horwitz had a sacrifice fly to deep center in his first plate appearance against his former team.

After giving up a one-out single in the third, Gausman retired 11 of the next 12 batters. The run of success ended with Garcia’s leadoff single in the seventh. Rodriguez’s single to center sent Garcia to third, but the Pirates were unable to push across a run.

Garcia remained stationed when Esmerlyn Valdez and Jake Mangum grounded out to first. Gausman gave way to the left-handed Fluharty, who needed just one pitch to retire Oneil Cruz on a fly ball to left.

In his major-league debut, Valdez went 0 for 3 with a walk. He struck out twice.