To win the Supporters' Shield, Atlanta United needs only to defeat Toronto on Sunday in the final week of the regular season.

But to win, Atlanta United must play better than it did in defeating Chicago 2-1 Sunday and than it has in the past several weeks.

“At this stage of my career, I’m not satisfied with just getting the win, if we haven’t had a good performance,” Atlanta United manager Gerardo Martino said after watching Franco Escobar score his first goal, and Chicago scoring an own-goal to produce two out of a very few pieces of excitement at a packed Mercedes-Benz Stadium.

It's continued a trend in which, outside of the first half against Colorado in which it scored three goals, Atlanta United hasn't been as ruthless as it once was. Still, the team leads MLS in goals (69) and goal difference. It also broke the league record for wins in a season (21) and is tied for the most points in a season (69).

“We know we need to compete for 90 minutes,” Martino said. “You can’t play mostly a good game, and then have lapses where you lose control of the game. We have to make sure we are focused for 90 minutes in Toronto. Against them, we know it’s going to be difficult, and we have to do our job for the full game.”

At stake in the regular-season finale is the Supporters’ Shield, a coveted trophy for the best record, and home-field advantage in the playoffs.

Martino said some of the lapses in the second half against Chicago can be explained by the absences of injured players Miguel Almiron (hamstring), one of the best players in MLS, and Hector Villalba, a speedster who stretches the defenses. Missing the same game for the first time in their careers, Atlanta United was without their combined 19 goals and 23 assists. Additionally, each has the ability to turn a game in the few seconds it can take them to dribble from midfield to the penalty box, leaving defenders in their wakes.

In their places, Martino put together a unique 18 that included five players aged 22 or younger. Within the 18, he chose to start Andrew Carleton, 18 and making his second start this season, and Ezequiel Barco, 19, and starting for the first time in six weeks, in a fluid midfield.

Both players had solid moments, but neither were credited with creating any scoring chances to help spark Atlanta United’s offense. Both did make several good passes.

“There were times when I flowed in and out of the game, but I got them the ball, and I did pretty well for making some stuff happen,” Carleton said.

Carleton and Barco could be in line to start the pivotal game at Toronto because it seems unlikely that Almiron and Villalba will be available.

“It doesn’t matter who’s in the (starting) 11, or who’s in the (match day) 18, we understand that we’re only as good as our weakest link, and that guys have stepped up throughout the season in big games and big moments,” captain Michael Parkhurst said. “Andy (Andrew Carleton) to come in here today and start in a big game, did well. (Ezequiel) Barco hasn’t started in a while; Franco (Escobar) as well, so really important minutes those guys put in today, and a good shift. You know, that’s the reason we’re in first place. It takes a big team to do what we’re doing right now, and we’ve been priding ourselves on that.”