TORONTO -- The Blue Jays suddenly find themselves on the ropes in the most unexpected of ways after an early stumble from Alek Manoah and a dormant offense led to a 4-0 loss to the Mariners in Game 1 of the AL Wild Card Series on Friday.

Manoah’s first inning was the ultimate outlier coming off his spectacular regular season, but in a best-of-three series, this is a cruel and sudden reminder for the Blue Jays of just how fragile these postseason runs can be.

After hitting Julio Rodríguez with a pitch in a two-strike count to open the game, Manoah gave up a double to Eugenio Suárez and then a two-run shot to Cal Raleigh, the author of another massive Mariners moment after his walk-off home run clinched Seattle’s first postseason berth since 2001. It was like a boxer being punched in the face a few seconds into a fight, quieting a raucous Rogers Centre.

“I just had to tell myself: Execute pitches,” Manoah said. “It was a pretty lengthy at-bat with Cal and ended up not executing the front-hip sinker. I just continued to tell myself: Continue to execute. They beat me on my mistakes, and I felt like I was able to start executing after that.”

From there, Manoah was his old self. He looked like the 24-year-old who’s kicked the door down, posting a 2.24 ERA over 196 2/3 innings this season and emerging as the Blue Jays’ ace. Toronto couldn’t have been more confident in Manoah entering Game 1, and rightfully so, but even the slightest misstep was enough to sink the Blue Jays on a day that Luis Castillo simply dominated their lineup.

Castillo was operating well above his season averages, regularly touching 100 mph with one of the most impressive performances of his career. Even when the Blue Jays snuck a handful of baserunners on in the middle innings with some fortunate base hits, the Mariners’ ace remained in full control, making his biggest pitches in the biggest moments.

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From Castillo, the Mariners went to Andres Muñoz, whose fastball reached as high as 102.9 mph. It was all gas, all the time. There were times where it looked nearly impossible to barrel up a pitch from Castillo.

“He's got two different fastballs at that level. He has a sinker pounding out your hands at 99 to 100, and then he has the four-seam that he'll throw up and away,” explained Whit Merrifield. “It doesn't have that dive. It's got more of a true carry. You're having to make a decision on what that 100 mph pitch is going to do, and that's what makes it tough.”

Manoah was lifted after 5 2/3 innings on 79 pitches, taking a slow walk to the dugout before slamming his hat to the ground. Even after pitching up to his talents from the second inning on, Manoah expected more, and understandably so after one of the best seasons from a pitcher in the American League this season.

“He settled in great after the first inning. I don't know if he was a little bit fired up,” manager John Schneider said, “but had some velo and just a couple of bad pitches -- 0-2 to Julio and the 3-2 heater to Raleigh. He retired 12 out of the next 14 after that.”

This is where the Blue Jays’ hope has to lie now, in Manoah getting another shot.

Kevin Gausman is scheduled for Game 2 on Saturday, a must-win game against Mariners lefty Robbie Ray, who won the AL Cy Young Award with these Blue Jays just a year ago.

Despite Friday’s setback, Manoah is exactly who you want back on the mound as soon as possible, given what he’s done over the past two seasons. And if a potential Game 3 rolls around, Manoah will surely be in the ear of pitching coach Pete Walker and Schneider, telling them that he’s ready on very short rest.

Now Manoah knows what the postseason feels like. Rogers Centre was rocking in the first inning, with chants as Manoah stepped atop the mound and a roar for his first strike. Like so many Blue Jays experiencing a home game in the postseason for the first time, though, Friday was a lesson.

“It was good to get the feet wet. I went out there and grinded as much as I can,” Manoah said. “Today wasn't good enough.”

If tomorrow isn’t good enough, the Blue Jays will be staring at a long wait until pitchers and catchers report to Spring Training next February.