TORONTO (Interstat) — On the penultimate day of a grueling American League East race, the Toronto Blue Jays took a significant step toward their first division crown in a decade. Rookie right-hander Trey Yesavage earned his first major league victory with five shutout innings, Alejandro Kirk provided a late exclamation point with a solo home run, and the Blue Jays defeated the Tampa Bay Rays 5-1 on Saturday evening at Rogers Centre.

The victory, played before a charged sellout crowd of 42,624 in 2 hours and 30 minutes, pushed the Blue Jays (93-68) into sole possession of first place. They entered the day tied with the New York Yankees, who were playing the Baltimore Orioles. Toronto can now clinch the AL East title and the league’s best record by matching or bettering the Yankees’ result in Sunday’s regular-season finale. The Blue Jays hold the tiebreaker, having won the season series against New York eight games to five.

Yesavage (1-0), a highly-touted prospect making just his third big league start, was the story early. He navigated traffic effectively, scattering five hits and striking out five without walking a batter. The Rays (77-84) put runners in scoring position against him in the first and third innings, but each time the 21-year-old right-hander escaped unscathed, including striking out Jonathan Aranda with the bases loaded to end the third.

“His poise was exceptional,“ Blue Jays manager John Schneider would have said, according to team officials. “To make a start of this magnitude and deliver like that, it’s exactly what we needed.“

While Yesavage kept Tampa Bay at bay, the Toronto offense broke through against Rays starter Joe Boyle (1-4) in the second inning. Addison Barger started the rally with a sharp single to left, and Davis Schneider worked a walk. After two outs were recorded, Ernie Clement laced a two-run double down the left-field line to open the scoring. Andrés Giménez followed by driving in Clement with a single to right, staking the Blue Jays to a 3-0 lead.

Boyle lasted five innings, allowing four runs on five hits with five strikeouts and two walks. His final run allowed came in the fifth inning, when Clement singled, advanced on a flyout, and scored on a two-out single by Nathan Lukes, extending Toronto’s advantage to 4-0.

Tampa Bay’s lone response came in the top of the sixth inning off Blue Jays reliever Yariel Rodríguez. Aranda led off the frame by launching a solo home run, his 14th of the season, to center field to break up the shutout. Rodríguez would strand a runner, however, striking out Carson Williams to end the threat.

The Blue Jays’ bullpen, a strength all season, was dominant the rest of the way. Justin Bruihl, Tommy Nance, and Seranthony Domínguez combined for three perfect innings of relief, striking out five batters between them. Domínguez was particularly sharp in the eighth, striking out two.

Kirk provided an insurance run in the bottom of the seventh, turning on a pitch and sending a towering solo shot, his 13th of the year, into the left-field seats to re-establish a four-run lead at 5-1.

The Rays, who also managed seven hits in the game, could not muster any further offense. They went 0-for-5 with runners in scoring position and left seven men on base. Pete Fairbanks and Griffin Jax provided scoreless relief for Tampa Bay, but the damage had already been done.

The result continued a recent trend of Blue Jays dominance in the season series, giving them their fourth consecutive victory over the Rays after dropping three straight in the set just over a week ago. The win also validated the pregame projections, as Toronto entered as a 1.5-run favorite and Interstat’s ELO system gave them a 58.7% chance of victory. The final score of 6 runs fell well under the posted over/under of 8.5.

All attention now turns to Sunday, where a season of work comes down to one final day. The Blue Jays will send their ace to the mound with a chance to finish the job, while the Rays will look to play spoiler and end their disappointing season on a high note. First pitch for the regular-season finale is scheduled for 3:07 p.m. EDT.