The Ole Gunnar Solskjaer era at Manchester United finally came to an end, and it ended in the most humiliating fashion. United lost 4-1 to newly promoted Watford in the Premier League on Saturday, which proved to be the final straw for the Norwegian.In what was another catastrophic display, the Red Devils were rolled over by Claudio Ranieri's spirited Hornets, who secured a memorable victory. Joshua King, Ismaila Sarr, Joao Pedro and Emmanuel Bonaventure were among the goals for the hosts. Meanwhile, United captain Harry Maguire saw red for the visitors, piling on the misery for Solskjaer.It was their fifth defeat of the league campaign, leaving United trailing leaders Chelsea by 12 points and seven points adrift of the top four. With United now seeking a new manager to revive their flagging fortunes, here are five key stats from their humiliating defeat at Watford:#5 Harry Maguire gets sent off for the second timeMaguire was sent off for two bookable offences.No matter how poor his current form may be, Harry Maguire had never been sent off in his Manchester United career before. But that ended last evening. With a red card in the 4-1 loss to Watford, the ex-Leicester City player was ejected from a game for the first time in 121 games for the club.OptaJoe@OptaJoe1 - Harry Maguire has been sent off for the first time in his Manchester United career, in what is his 121st appearance for the club. Ears. #WATMUN10:01 AM · Nov 20, 20219431541 - Harry Maguire has been sent off for the first time in his Manchester United career, in what is his 121st appearance for the club. Ears. #WATMUNIt was also only his second-ever sending off. Maguire last saw red in Leicester City colours in March 2019 during a 2-1 win over Burnley. He was sent off in just the fourth minute on that occasion.#4 Donny van de Beek reprises his Manchester United supersub roleDonny van de Beek scored the last United goal of the Ole Gunnar Solskjaer era.For the first time since netting on his Manchester United debut in September 2020, Donny van de Beek was on target for them again last night. Coincidentally, he' struck both goals after coming off the bench.OptaJoe@OptaJoe2 - Donny van de Beek's two Premier League goals have both come as a substitute, with this his first since netting on his debut against Crystal Palace in September 2020. Lifeline? #WATMUN9:41 AM · Nov 20, 2021452732 - Donny van de Beek's two Premier League goals have both come as a substitute, with this his first since netting on his debut against Crystal Palace in September 2020. Lifeline? #WATMUNLast year, it took him just 13 minutes after being subbed on to get on the scoresheet. Against Watford on Saturday, the Dutchman needed only five. However, both of his goals have come in losing causes - a 3-1 loss to Crystal Palace at home and now a 4-1 reverse to Watford on the road.