Kylian Mbappe and Erling Haaland wasted little time making their mark as the Champions League returned Tuesday, with Real Madrid and Manchester City opening the new season with victories.

Mbappe scored early for record 15-time champions Madrid, who beat Inter Milan 2-1 at the Santiago Bernabeu. Haaland went one better, scoring both goals as City, the 2023 champions, defeated Porto 2-0.

Madrid and City are expected to be among the leading challengers to two-time defending champions Paris Saint-Germain this season, with both teams again relying heavily on their prolific forwards.

Mbappe opened the scoring after 14 minutes, taking his Champions League total to 71 goals and moving level with Madrid great Raul for fifth on the competition's all-time scoring list.

Haaland, meanwhile, continued his remarkable scoring rate in Europe's premier club competition. His two goals against Porto took his Champions League tally to 59 in 59 appearances.

Elsewhere, Borussia Dortmund edged Villarreal 3-2, while Real Betis also claimed a 3-2 victory, beating Lille in France.

Aston Villa also beat Club Brugge 3-2, while AEK Athens defeated LASK 1-0.

PSG begins its campaign Wednesday against Slovan Bratislava.

Jose Mourinho made a winning return to the Champions League as Madrid's head coach despite Inter dominating possession.

It was a classic Mourinho-inspired performance as Madrid capitalized on two first-half errors by the visitors.

When Inter lost possession deep in its own half, Brahim Diaz slid the ball to Mbappe, who fired low past Josep Martinez.

The Inter goalkeeper was then guilty of indecision when Federico Valverde closed him down in his own area and poked the ball into an empty net.

Inter, which ended the game with 61% possession, set up a tense finish when Carlos Augusto scored in the 77th minute.

"There's so much criticism when a game is boring, but today it was crazy. It could easily have ended 7-6," Mourinho told broadcaster Movistar.

Mourinho won his second Champions League title with Inter in 2010 and is aiming to join Pep Guardiola, Luis Enrique and Zinedine Zidane by lifting the trophy for a third time.

With five goals in his last three games, Haaland is in hot form. It could have been even more if not for Porto goalkeeper Diogo Costa's first-half performance.

Haaland eventually found the breakthrough at Estadio do Dragao with a header two minutes into the second half. He side-footed City's second goal in stoppage time to make certain of the win and ensure new coach Enzo Maresca's 100% start continued.

"We have to learn. Enzo demands a lot from us and we have to demand a lot from each other," Haaland told Amazon Prime. "We have to win games because at Man City, you have to win trophies. That's what we have to do at this club."

Aston Villa put their domestic problems behind them with a win over Club Brugge.

Victory in Belgium ended Villa's winless and goalless start to the 2026-27 season after early struggles in the Premier League.

John McGinn recorded the first goal of the Champions League campaign with a sweeping low shot from an angle in the 11th minute. Hugo Vetlesen equalized for Brugge, but Emiliano Buendia and Nicolas Jackson put Villa 3-1 up by halftime.

Nicolo Tresoldi scored for the home team from the penalty spot in the 61st minute, but Villa held on for the win.

Villa coach Unai Emery will hope the victory sparks his team's season after the summer departures of star players Morgan Rogers, Ollie Watkins, Ezri Konsa and Emi Martinez.

His much-changed team lost to Brighton and Arsenal in the Premier League and picked up its first point of the season with a goalless draw against newly promoted Hull on Saturday. Villa had recorded only one shot on target in those three games.

Borussia Dortmund teenager Konstantinos Karetsas was taken to the hospital after slumping to the turf 25 minutes into his Champions League debut.

"Konstantinos Karetsas had to leave the field due to circulatory problems," Dortmund said in a statement. Karetsas "is doing well under the circumstances and is on his way to the hospital for further tests."

Serhou Guirassy scored three goals, two for Dortmund and one in his own net, in a frantic finish against Villarreal.

Guirassy gave Dortmund a 2-1 lead in the 80th minute and then struck again from the penalty spot five minutes later.

An added-time own goal made it 3-2.

It has been an eventful few days for Troy Parrott.

The Ireland international scored his first goal for new club Betis with a late winner against Madrid on Friday, and he was on target again with the decisive goal in the 3-2 win at Lille.

AEK Athens beat LASK 1-0 thanks to Razvan Marin's brilliant first-half free kick.