Haaland threw the ball against the back of Gabriel's head, an unacceptable action that came at a moment of high emotions, and was deemed out of order.
Trossard's second yellow card was correct, but inconsistencies in decision making, such as unpunished incidents involving Doku and Joao Pedro, have raised concerns about referee consistency.
Barcelona goalkeeper Marc-Andre ter Stegen will undergo surgery on Monday after suffering a complete rupture of the patella tendon in his right knee against Villarreal.
Time-wasting should be punished by yellow or second yellow cards, as it is not an acceptable part of the game, especially in result-based competitions.
Arne Slot has made a good start, but it's early in the season, and while Liverpool have enough quality to make a challenge, winning the title may be a stretch.
BBC Sport readers voted David Raya as the best Arsenal player, with other highly rated players including John Stones, who scored the late equalizer for Manchester City.
Rodri's injury could have a significant impact on Manchester City's chances of extending their run of four successive Premier League titles, as he is a crucial player in the City squad.
While Rodri's injury is a concern, Manchester City have options in the center of midfield, including Mateo Kovacic and the returning Ilkay Gundogan, but no one can replace Rodri.