OAKLAND -- With Adrían Martínez going through the early stages of his first year with a new organization, the A’s are still trying to get a feel for what type of pitcher they have in the right-hander, who was acquired in the early April trade that sent Sean Manaea to the Padres.

A strong fastball-changeup combination was among the standout qualities on display in Martínez's third Major League start on Tuesday night, a 5-3 win over the Blue Jays. The trait that left an even greater impression on manager Mark Kotsay, however, was more of the intangible type.

“He’s a competitor,” Kotsay said of Martínez. “That’s really what I like about him. He goes out and takes the baseball and you thoroughly know he’s enjoying being out there pitching.”

Martínez indeed showed a fighting spirit. Though he was knocked down a couple of times after surrendering home runs to Matt Chapman and Teoscar Hernández, the 25-year-old picked himself back up each time and continued battling. By the end of his five-plus innings, Martínez departed with a solid line, holding a powerful Blue Jays offense to three runs on eight hits and no walks with five strikeouts.

The win put Oakland in line on Wednesday afternoon to possibly sweep a series for the first time in 2022. It also secured the club’s first series victory at home since April 18-21 against Baltimore.

A breakout 2021 campaign for Martínez in San Diego’s Minor League system that vaulted him onto the club’s Top 30 prospects list is what excited the A’s about landing him as part of the return for Manaea. Called back up last month and now getting an extended look, Martínez, Oakland’s No. 21 prospect per MLB Pipeline, is being given a chance to fully develop as a big leaguer by working closely alongside A’s pitching coach Scott Emerson.

There were immediate signs of improvement in contrast to Martínez’s previous start on Thursday, when he took a loss in Seattle after allowing seven runs over 4 2/3 innings. This time around, A’s catcher Sean Murphy noted that Martínez asserted himself a bit more on the mound.

“He came out and pitched his game more,” Murphy said. “He knows himself. He was doing what he wanted to do. He knows how he’s effective and he did a great job of walking me along with him. He took the lead out there, and I think that helps him.”

The most effective offering in Martínez's three-pitch arsenal on Tuesday and the pitch that will likely determine his long-term fate with the A’s is his changeup. Described as a plus pitch by scouts, Martínez is able to throw it in any count, ranging from 82-84 mph and offering hitters a significant variation in speed from his fastball, which maxes out around 95-96 mph.

Against Toronto, he went to the changeup in tough spots, throwing it 31 times and generating nine of his 13 whiffs (swings and misses) with the pitch, including the putaway pitch to all five of his strikeouts.

“I had a lot of confidence in that tonight,” Martínez said of his changeup. “In 2-0 counts, I was using it and it was very effective. I think it’s one of my best pitches and I’m going to keep going forward with it.”

Of course, there are other aspects of his game that still need some fine-tuning. Kotsay mentioned he’d like to see an improvement from Martínez’s slider, a pitch that missed the zone too often and led to him falling behind in the count on both homers he allowed.

“Still work in front of us with him,” Kotsay said. “He’s got a lot of room to improve. Overall, the mix is there and the stuff is there. We’re going to continue to improve his mechanics and get him on line.”

Though he’s only a rookie, Martínez has quickly earned praise from more established teammates for his poise and presence, which bodes well for his future. A’s outfielder Stephen Piscotty, who provided some offense with a booming 431-foot solo homer halfway up the left-field bleachers in the fifth, is among those who continue to be impressed.

“I like how he attacks the zone,” Piscotty said of Martínez. “He was aggressive and we were ready to make plays for him. He’s not trying to get cute or anything. I really appreciate that style of pitching as a defender. I think that plays here. He’s looked really good.”