The Union’s 3-0 win over the Montreal Impact on Saturday produced lots of good storylines to analyze.

Here are a few worth focusing on, plus a bonus note on Sky Blue FC ahead of their biggest game of the spring:

Jim Curtin makes another good tactical switch

On paper, the Union set up in a 4-4-2 formation like they usually do. Ilsinho was listed as one of the two forwards, which was surprising. The Brazilian probably wouldn’t even call himself that.

In reality, the Union lined up in more of a 4-1-4-1, with Ilsinho often moving to his more natural place on the right wing. Alejandro Bedoya lined up next to him, followed by Jamiro Monteiro and then Brenden Aaronson on the left. There was a lot of interchange within the line of four, as a way of forcing Montreal’s entrenched back line to chase the ball.

Brenden Aaronson provided the two best examples of that. His nifty backheel flick in the first half came on the right side of the 18-yard box, as did his efforts to win the corner that led to the penalty kick for the Union’s second goal.

A hat tip to Matt Doyle of MLS’ website staff for charting Aaronson’s movement on the latter sequence:

Jamiro Monteiro as a No. 10

If the Union weren’t really playing a 4-4-2, then Monteiro wasn’t really playing the pure No. 10 role that he was listed as. But he was definitely in a central role, and Aaronson was often on the left, which means Monteiro was tasked with filling the hole left by Marco Fabián’s absence.

Monteiro totaled 58 touches, 1 shot, 5 tackles, 1 interception and a goal from the penalty spot, completed 36 of his 44 pass attempts.

“It’s not a big difference — for me, it’s still in the midfield, only I play more in the front,” Monteiro said after the game. “It’s not the first time I’ve played the No. 10, so it was not difficult.”

Aurélien Collin steps up on short notice

Curtin said he woke up at 6 a.m. Saturday to a text message that Mark McKenzie had emergency surgery Friday night for appendicitis. Aurélien Collin probably had his morning upended not long thereafter, since he was now suddenly going to make his Union debut in the starting lineup.

Despite the short notice, Collin had a very nice game: 69 touches, 4 tackles, 3 blocked shots, 2 interceptions, 2 clearances and 1 aerial dual won. He also completed 42 of his 54 pass attempts, including 6 of 10 long balls.

Kai Wagner will be missed

The slide tackle that earned Kai Wagner a red card in the final minutes of the win remains as poor a decision by the player now as it was in the moment. It was studs-up, reckless, and entirely unnecessary at that point in the game.

Now the Union will be without a player who is not just their starting left back, but one of the best left backs in the league.

According to WhoScored.com’s data, Wagner ranks No. 3 leaguewide among left-sided defender in total chances created (8), No. 5 in accurate crosses (5), No. 4 in accurate long balls (14), No. 2 in accurate short passes (262) and No. 1 in total tackles (27).

Montreal star kept from shining

If Samuel Piette played for the Union, he’d be a cult hero. The Quebec-born defensive midfielder is built like a linebacker and plays like one for the Impact and Canada’s national team.

The Union did a great job of limiting Piette’s effect on the game. Though he had 60 touches, he recorded zero tackles, and just 2 interceptions, 1 clearance and 2 aerial duals won.

Focus turns to Sky Blue FC

With the Union headed out to Vancouver this weekend, the only game on the local pro soccer landscape will be at Sky Blue FC. And it’s a big one: Carli Lloyd’s team hosts the star-studded Portland Thorns, led by New Jersey native Tobin Heath and fellow U.S. national team star Lindsey Horan, on Sunday at 6 p.m. at Rutgers’ Yurcak Field.

Heath’s returns to her home state are always spectacles, but this game has extra significance. It’s the last one before U.S. players leave for the team’s pre-World Cup training camp, which is expected to start in the first few days of May. The Americans play their first World Cup sendoff game on May 12 against South Africa in Santa Clara, Calif, and U.S. coach Jill Ellis will have confirmed her 23-player World Cup roster by then.

The U.S. Soccer Federation hasn’t yet said exactly when the roster will be announced, but it won’t be a surprise if it happens this week.

Sky Blue has started the season 0-2, with a 2-0 road loss to the Washington Spirit and a 1-0 home loss Saturday to the Houston Dash, but they’re playing better and more energetic soccer than they did last season.

Portland kicked off with a 2-0 win at the Orlando Pride, then played a wild 4-4 tie at the Chicago Red Stars on Saturday. Heath had a backheeled goal and a backheeled assist in the first game, and Horan had a great chipped assist to Christine Sinclair in the second.