The Union won their debut game in the Concacaf Champions League, 1-0, at Costa Rica’s Saprissa on Wednesday, with a first-half goal from Kacper Przybylko and a lot of defense that included surviving a bench-clearing brawl in the final seconds.

Przybylko did the honors in the 34th, set up by a beautiful cross from Olivier Mbaizo on the right flank. It was the perfect start to the year for Przybylko, who overcame back spasms (with help from an injection) to be healthy for the game.

It was also a fine statement by Mbaizo in his first start at right back since Ray Gaddis’ offseason retirement. And there’s the added bonus of away goals serving as the first tiebreaker if the series score ends tied.

That was the only goal of a first half in which you couldn’t tell it was the Union’s first game of the year — and Leon Flach’s first appearance for the team. Flach started on the left side of the Union’s diamond as Jamiro Monteiro moved up to the top of it, and Anthony Fontana started on the forward line with Przybylko.

José Andrés Martínez had an especially good first half, completing 29 of 34 passes.

As the clock ticked on, the questions became not just about whether the Union could get a second goal. Jim Curtin hinted before the game that Przybylko likely wouldn’t be able to go all 90 minutes, and the Union had no forwards on the bench. But Przybylko lasted past the first substitution, Matt Real replacing Flach and shifting the Union’s formation to a 4-2-3-1.

» READ MORE: A year after winning their first trophy, are the Union good enough for an encore?

The move allowed Mbaizo and left back Kai Wagner to sit deeper and focus on defending for the rest of the game.

A foul moments later gave Saprissa a dangerous free kick, and Andre Blake was lucky that big centerback Kendall Waston — plenty familiar to the Union from his years in MLS — headed the service wide.

Saprissa came even closer to equalizing in the 70th when another former MLS player, Christian Bolaños, headed a corner kick toward the far post. But Kai Wagner was standing on the goal line and launched a header high to save the day.

The game turned fractious from there, and the tackles in both directions got sharper. A big slide by Real in the 75th earned a yellow card, which predictably sent a crowd of players swarming to Salvadoran referee Ismael Cornejo.

Curtin waited as long as he could to make another substitution, finally withdrawing Przybylko for academy-bred rookie Quinn Sullivan in the last minute. Saprissa had made a few subs before then, including bringing former Union reserve team defender Walter Cortés on in the 86th minute.

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The game ended with the Union’s true introduction to the Champions League. Bolaños hit a centering pass that slammed into Wagner’s chest, then Ricardo Blanco upended Wagner with a ferocious tackle. Jakob Glesnes shoved Blanco in retaliation, then Saprissa’s players stormed over and the team’s bench joined the fray.

Blake and Alejandro Bedoya rushed in to pull their teammates out, though Glesnes kept at it for a moment longer.

Eventually the dust settled with yellow cards given to Saprissa’s Blanco, Michael Barrantes and Daniel Colindres, and the Union’s Glesnes and Monteiro. Cornejo blew the final whistle right after play resumed.

The Union will now bring the lead home for the second leg of the series next Wednesday at Subaru Park (8 p.m., FS1).

”We’re at halftime right now in a good position … Our goal was to survive and advance,” Curtin said. “I give the players a ton of credit on the field for showing a lot of heart.”