OAKLAND -- Perfection over the course of a full season is an impossible task for any bullpen, though the A’s relief corps had managed to remain pristine for over a full month into the 2021 campaign.

On Wednesday night -- 32 games into the season -- the bullpen finally had its first off-night.

Everything was following what has been the usual script for the A’s. After seven impressive innings, right-hander Chris Bassitt handed over a one-run lead to a bullpen that earlier in the day received heavy praise from manager Bob Melvin for its continued dominance to help Oakland to the best record in the American League. But throughout that dominance has also come heavy usage, which may have led to the rare implosion in a 9-4 loss to the Blue Jays.

“We’ve won a lot of games doing it the way we were about to do it,” Melvin said. “They’ve got a pretty good hitting lineup that we’ve held down for a while and they ended up having a big inning.”

A’s relievers entered the day 7-0 with a 3.50 ERA and a perfect 9-for-9 tally in save opportunities -- the only relief corps in the Majors without a loss and one of only two clubs without a blown save.

By the time Lou Trivino walked off the mound in the eighth, both of those perfect stats were on their way to being dissolved as the right-hander gave up the lead by allowing three runs on two hits and departing after recording just one out. At the conclusion of the inning, Trivino was charged with five earned runs, allowing more runs in that one-third inning he worked than the three earned runs he had given up across 17 innings coming into the night.

Trivino made no excuses after the game. Frustrated with his performance -- which began ominously by issuing a walk to Toronto’s ninth-place hitter, Reese McGuire -- he chalked it up to just having a bad night.

“I just didn’t execute pitches,” Trivino said. “Bass threw a fantastic game. I thought we played really good baseball, and then I just crapped the bed. Just not my day. I gotta forget about it.”

A total of seven runs allowed in two innings by the bullpen spoiled what was Bassitt’s longest outing of the season. Navigating through a rough first in which he gave up two runs on four straight singles, Bassitt turned it around in a major way. Following an RBI single by Randal Grichuk in the first, he proceeded to retire 20 of the final 21 batters he faced.

Pulled with 90 pitches, Bassitt ended up allowing just two runs on six hits. He did not issue a walk and struck out seven, marking his fourth consecutive outing in which he’s recorded at least seven punchouts.

“He was fantastic after [the first],” Melvin said. “He’s come a long way, not only as a pitcher, but understanding you can’t let one inning beat you. You have to just put it to bed and do your thing. That’s exactly what he did.”

For the past few years, Bassitt has exhausted his efforts to integrate an effective slider into his repertoire, to little avail. During Spring Training, with the help of pitching coach Scott Emerson and relievers Jake Diekman and Sergio Romo, who both provided tips on using a grip similar to theirs, Bassitt made a breakthrough in his quest to add the pitch. He’s even got some flair to his new slider, throwing it at a different arm slot from his other pitches to throw hitters off balance.

Entering Wednesday’s start, Bassitt’s revamped slider ranked as one of the most dominant pitches in baseball. According to Statcast, his 63.6 percent whiff (swing and miss) rate on the slider was the fifth-highest of any single pitch among all Major League pitchers. Against Toronto, Bassitt threw the slider 10 times and induced four whiffs with it, the most he recorded on any of the six different pitches he threw.

“I think it’s a big weapon for me,” Bassitt said. “We’ve been trying for freaking years to try to throw a slider. I’m not a huge spin guy. I don’t spin the ball well. But I’m able to take velo off pitches. Once we figured that out, I think it’s just trying to mimic my sinker arm slot. We’ve done a good job of that.”

As for the rare bullpen struggles, which denied him his third win of '21 after holding a lead provided to him on two solo homers by Ramón Laureano and Matt Chapman along with a Sean Murphy go-ahead RBI single in the sixth, Bassitt’s confidence in the bullpen did not waver. To him, this was just a minor blip on the radar.

“It’s unfortunate that it happened tonight. But I think it’s also a testament to how great our bullpen is,” Bassitt said. “It’s going to happen, hopefully, very few more times throughout the year. I still fully trust Lou and our back end of our bullpen. If I ever get pulled and see those guys coming in, I’m not mad one bit.”