Flop #1: Marcos Rojo (Manchester United)

Marcos Rojo was, in our opinion, the worst player on the pitch. It was also his first Premier League start of the season, and it was a night to forget for the Argentinian.
On three occasions, he lost the ball due to poor touches, and also was fouled twice. His dive on to Gunners' youngster Matt Guendouzi was potentially a red-card offence, though he escaped with a yellow. He was also ineffective in his primary role in defense, clearing the ball out of danger just twice and making a block just once.
To make it worse, in the 68th minute, he sloppily conceded possession to Mkhitaryan, with the latter then combining with Lacazette to burst into the final third. Rojo simply clattered back and attempted a knock on to the Arsenal striker, catching the ball instead and diverting into his own net. Had Lingard not equalized later, it would have handed the Red Devils yet another loss at Old Trafford.
United manager Jose Mourinho substituted him off for Marouane Fellaini immediately after the grave error.