The greatest walk-off that didn't really count

Two years ago on this date, Vladimir Guerrero Jr. crushed a walk-off homer against the Cardinals in an exhibition game. While the blast didn't count as far as the official Major League record book is concerned, it carried a great deal of significance nonetheless.

Why? The home run came at Olympic Stadium in Montreal, where Guerrero's father, Hall of Famer Vladimir Guerrero, spent the first eight years of his career.

Vlad Jr.'s first real walk-off homer will surely be a memorable occasion, but it's going to be difficult to top this one, Spring Training or not. Here's everything that made the moment particularly special.

The history: The elder Guerrero not only was one of the greatest players in Montreal Expos history, but also the franchise's last superstar before it moved to Washington D.C. and became the Nationals. Although his final game with the Expos came in 2003, Guerrero is still revered in Montreal.

Over eight seasons with the club, Guerrero hit .323/.390/.588 with 234 home runs and 123 stolen bases, making four All-Star teams in that time. He ranks first in Olympic Stadium history with seven walk-off homers, three more than any other player.

The Blue Jays, now Canada's only Major League team, began playing exhibition contests at Olympic Stadium in 2014, drawing more than 96,000 fans combined in two games the first year.

In July 2015, Toronto signed the younger Guerrero as an amateur free agent out of the Dominican Republic, and by March '18, the prospect hype surrounding the third baseman was starting to grow.

Guerrero was coming off his first full professional season, having hit .323/.425/.485 with 13 homers and an impressive 76-to-62 BB/K ratio over 119 games between Class A and Class A Advanced as an 18-year-old.

Guerrero appeared in only two Grapefruit League games before the Blue Jays' Montreal trip in 2018, but the club decided to bring him and fellow prospect Bo Bichette north.

The number: When Guerrero played for the Blue Jays earlier that spring, he sported No. 83. But during the team's series in Montreal, Guerrero wore No. 27, the same number his father wore for his entire career. Guerrero said that he didn't request the number switch but found out about it when he saw that the team had packed a No. 27 jersey for him as a surprise prior to the trip to Canada.

In the first game of Toronto's series against St. Louis, Guerrero entered as a sub at third base in the top of the seventh inning. This wasn't his first time on the Olympic Stadium turf. Here he is at age 3, decked out in full uniform before an Expos game against the Braves in 2002.

When his name was announced, Guerrero was greeted with a standing ovation from the crowd of more than 25,000. It was more of the same when he came to the plate for the first time in the bottom of the seventh.

Guerrero ended up going 0-for-2 with a lineout and a groundout in the first game. He would have a bit more success the next day.

The matchup: Even if you remembered Guerrero's walk-off dinger in Montreal, you might have forgotten that it came against Jack Flaherty. The right-hander's involvement provides even more intrigue, as he has gone on to become one of the very best pitchers in baseball. This early showdown between the two could take on added meaning if Guerrero and Flaherty dominate the game for the next decade.

At the time, Flaherty was MLB's No. 38 overall prospect, while Guerrero was No. 3. With Adam Wainwright suffering a hamstring injury late in Spring Training, Flaherty was set to open 2018 in the Cardinals' rotation. Guerrero, meanwhile, was headed for Double-A New Hampshire, but his home run further fueled the idea that he could be ready for the Majors sooner rather than later, despite being just 19 years old.

For the second straight day, Guerrero was a defensive replacement, taking over at third base in the sixth inning of a scoreless game. St. Louis summoned Flaherty in the seventh, and the righty proceeded to retire the first eight batters he faced, including four on strikeouts. Guerrero, however, put a stop to the streak, jumping on the second pitch he saw.

The pitch: Flaherty's slider is lethal. Over 2018-19, he ranked 11th in xBA (.172) and tied for 15th in xSLG (.287) on sliders (min. 1,000 sliders thrown). His whiff rate of 45.8% on sliders was the 11th-best mark in that span (min. 400 swings on sliders).

But on March 27, 2018, in the bottom of the ninth inning, Flaherty threw a hanging slider to Guerrero, and Vlad Jr. didn't miss. It was the final pitch of Spring Training for both clubs, with Opening Day coming two days later.

Guerrero's big fly -- the first walk-off homer at Olympic Stadium since Orlando Cabrera's on June 20, 2004 -- set off a frenzied celebration in the park, and he even got a curtain call after intially retreating to the dugout.

Following the walk-off jack, Guerrero went on to record a .381/.437/.636 slash line with 20 home runs over 95 games in the Minors in 2018, starting as the youngest player in the Eastern League (Double-A) and reaching Triple-A in July.

MLB Pipeline ranked Guerrero first on its list of the Top 100 prospects prior to the 2019 season. After being delayed by an oblique injury during Spring Training, Guerrero made his big league debut on April 26, 2019, and he ended up hitting .272 with 15 home runs and a .772 OPS over 123 games as a rookie.

As for Flaherty, he made 28 starts for the Cardinals in 2018, finishing fifth in the National League Rookie of the Year Award race after posting a 3.34 ERA. And last year, he rebounded from a slow start to register an eye-popping 0.93 ERA with a 0.70 WHIP over his final 16 starts.

Guerrero and Flaherty have not yet crossed paths in the regular season, as the Blue Jays and Cardinals haven't played each other since 2017.