As he prepared for the Union’s game against Toronto FC this past Wednesday, Union manager Jim Curtin was asked to rank the priority of his team’s next three contests: that one, Sunday’s visit to the first-place New Revolution (6 p.m., PHL17), and Thursday’s visit to Mexico’s Club América (10 p.m., FS1 and TUDN) for the first leg of the Concacaf Champions League semifinals.

“The Champions League one, Toronto two, and New England,” Curtin said, and no one disagreed with him.

The Champions League game is the biggest contest in club history. The Toronto game was at home, against a struggling opponent and after the Union had played poorly against even-worse Chicago.

And the New England game is, well, the kind where if it was the NBA, Joel Embiid might have a load management night.

If that offends you, avert your eyes. Because it’s probably in the Union’s interest to, you know …

“Obviously there is an eye on the Champions League, and that game has a priority,” Curtin said Friday. “But we’ll go one game at a time. I know it’s a cliché, but winning the Champions League certainly matters more than winning this game against New England.”

» READ MORE: Union rout Toronto FC, 3-0, to snap summer skid: Observations and analysis

Curtin wouldn’t give too much away, especially because there’s no coach he cares more about hiding his cards from than New England’s Bruce Arena. He insisted that he’d “to put a very strong team out on the field against New England to try to get points.”

But even though the odds are overwhelmingly against the Union facing América, the biggest club team on this continent (by a lot over any MLS team), Curtin knows the truth. He owes it to his team as much as to the fans and the competition to put the Champions League first.

Curtin also has to perform an unusual balancing act even by Concacaf standards: going from the artificial turf at New England’s Gillette Stadium to the 7,200-foot altitude and smog of Mexico City’s Estadio Azteca. It’s a wild swing of extremes to deal with in five days.

“And it’s a pretty good team that we’re playing too,” he said. “Look, we’re in the final four on this continent. As crazy as this sentence sounds, if we find a way to advance versus América and win one more game [the one-game final], you’re playing against the European champion Chelsea [in the FIFA Club World Cup].”

Curtin did not hesitate to add “as silly as it might seem,” and it is. América, led by Mexican striker Henry Martín and veteran goalkeeper Guillermo Ochoa, is the overwhelming favorite in the series. The Union’s best hope of an upset is to keep the game in Mexico City as close as possible, then come home for the second leg and try to pull off the greatest win in team history.

The winner of the other semifinal, an all-Mexican clash between Cruz Azul and Monterrey, is the likely favorite to win the tournament. That series starts Wednesday at Monterrey (10 p.m., FS1 and TUDN).

But the steep odds shouldn’t stop Curtin and his players from trying. Whatever adapting they have to do to be ready for the altitude, they should do. However much rest Curtin can give Alejandro Bedoya and other veterans — almost all of who have never played at such elevation before — will only help.

» READ MORE: Union’s Kai Wagner celebrates his first MLS All-Star team selection

“Regardless of who’s on the field, whether we rotate a couple guys here or there, you know, we want to play the same way and look the same” against New England, Curtin said, “and then build even more confidence going into a huge game at the Azteca.”

That was as close as Curtin came to admitting what everyone knows. And while it may go against Philadelphia sports orthodoxy, everyone should know it’s for the better.