Though his team was outplayed and looked flat for long stretches, Atlanta United manager Frank de Boer on Thursday unsurprisingly expressed confidence that his team can overcome its 3-1 deficit and take the second leg of their CONCACAF Champions League series.

The game will be played Thursday at Kennesaw State.

“I’m 100 percent sure we can get our revenge,” de Boer said. Actually, de Boer said something similar to that at least three times in his postgame press conference held in a small, stuffy room underneath the stands of Estadio Eladio Rosabal Cordero at the loss to Herediano.

The easiest way for Atlanta United to advance to the tournament quarterfinals would be to shut out Herdiano and score at least two goals. Though on aggregate the teams would be tied 3-3, Atlanta United would advance because it scored an away goal.

Should Herediano score one goal at Kennesaw State, Atlanta United would need to score at least three to force more soccer.

The task doesn’t seem too difficult for an Atlanta United team that features Josef Martinez, the reigning league MVP and holder of numerous scoring records, and Pity Martinez, the reigning South American Player of the Year, and a defense that has posted two of the better goal-differences in league history in each of the past two seasons.

“I’ll take those chances,” midfielder Julian Gressel said.

Atlanta United’s players also have the muscle memory of bouncing back from deflating losses in the club’s  previous two years.

The Five Stripes were drubbed 4-0 by Houston in last season’s opener. The team responded with an unbeaten run of eight games. It was beaten by Toronto in last year’s season finale, a defeat that cost the team the Supporters’ Shield. It won four of its next five to take the MLS Cup.

Atlanta United can also point to the fact that each of Herediano’s goals came from individual mistakes that can be fixed. While Herediano can point to the fact that it could have scored at least two more goals if not for saves by Brad Guzan, Atlanta United can say the same thing with missed chances or great saves on shots by Josef Martinez, Darlington Nagbe and Hector Villaba.

“No doubt we can do it,” Atlanta United captain Michael Parkhurst said.