Amid a record-breaking national summer heat wave, the new midseason Leagues Cup tournament involving all 47 teams from MLS and Mexico's Liga MX delivered on opening night.

That's when three games were decided by penalty kicks as well as a fairy-tale finish in superstar Lionel Messi's American debut Friday.

Some like it hot.

"These games are always a little bit picante when we play each other," Minnesota United defender Zarek Valentin said, using the Spanish word for spicy.

The Loons make their Leagues Cup debut Sunday night against Mexican side Club Puebla at home at Allianz Field. They continue their three-team group play Thursday against Chicago Fire, also at home.

At stake in a MLS season shut down over the next five weeks is nearly $40 million in prize-pool money and three spots in the CONCACAF Champions Cup.

Two teams advance to a knockout stage from each three-team group. It's a long wait for the team left behind after all three group teams face each other. The MLS season won't restart until Aug. 20.

"I want to win this competition if we can," Loons coach Adrian Heath said. "We're treating it seriously. Everybody who is available will be available for selection and we'll go try to win the game. There's a lot at stake for a lot of teams and I think the Mexico teams will take it really seriously. We will, too."

Club Puebla opened its season 0-2-1 while starting a different formation each time. Puebla is Mexico's fourth largest city. Its inland metro area has more than 3 million people living at 7,000-feet elevation in southern Mexico.

Heath said he'll field the best team possible for every game, although he indicated their opener won't include injured Mexican international Micky Tapias, Sang Bin Jeong and Franco Fragapane.

Games tied after 90 minutes go to a penalty kick shootout. Winners in regulation earn three points. Winners on penalty kicks earn two points and the shootout loser gets one.

"It's going to be important to get out of your group," Loons defender DJ Taylor said. "Teams that don't get out of their group are sitting there for three weeks doing nothing. We know training will be way harder if we don't get out. That's going to be a motivator for me. We're excited and I can't wait to get going."

Two Liga MX teams beat MLS teams on Friday, including Leon winning 16-15 on PKS in Vancouver. Two MLS teams beat two other MLS teams and Miami beat Cruz Azul 2-1 on Messi's sensational free kick in the 94th minute.

Valentin entered MLS in 2011 with Los Angeles-based Chivas USA just as another international superstar — David Beckham — was leaving LA Galaxy and the league by 2012.

"You couldn't write a better script, it was a good spectacle," Valentin said of Messi's winning goal Friday. "Messi is going to have a profound effect. I played with Beckham when he was with the Galaxy. That brought a plethora of new fans to the league. I think he can attract some new viewership and a new age of fans, young fans. It's important to have young people who want to go play soccer."

Heath said it's important to use the next five weeks to get newly acquired striker Teemu Pukki, forward Ismael Tajouri-Shradi and defender Ethan Bristow as well as star midfielder Emanuel Reynoso and Jeong all fitter and fully integrated with each other. He wants them to do so before the MLS season resumes. Bristow will leave next week to complete his visa immigration process.

"This month is important to get us prepared for the season's final 14 games," Heath said.

The Leagues Cup is intended to intensify the relationship and rivalry between the United States' and Mexico's top soccer divisions. Like Valentin, Heath predicts games will become picante, only he did so in English.

"I think we'll see some real intensity in the games," Heath said. "I like the competition. The rivalry between Liga MX and MLS is getting closer and I think that will show. You'll see some real high-tempo games and I think it can get a little bit feisty toward the end of the competition."