SUNDAY TIMES WEB DESK: In his first appearance back at the Emirates Stadium since swapping north London for Old Trafford a year ago, Sanchez silenced the inevitable boos to help continue Ole Gunnar Solskjaer’s remarkable start as United’s interim manager.

Sanchez and Jesse Lingard scored within two minutes of each other in the first half but Pierre-Emerick Aubameyang replied just before halftime to set up an engrossing second half.

Arsenal suffered injury blows, with defenders Sokratis and Laurent Koscielny both being forced off, although they pushed hard for an equaliser in the second period.

But United, who are second behind Arsenal in all-time FA Cup wins with 12, absorbed the pressure and sealed an eighth successive win for Solskjaer in the 82nd minute when substitute Anthony Martial tapped home after a counter-attack.

A feisty tie threatened to boil over late on with United substitute Marcus Rashford and Arsenal’s Sead Kolasinac squaring up near the touchline to spark a melee in which a coin was thrown from the crowd towards Lingard.

Rashford and Kolasinac were both booked with six yellow cards handed out in total by referee Craig Pawson.

United’s former Norwegian hitman Solskjaer arrived as a stop-gap with United at a low ebb after a rancorous few months under the sacked Jose Mourinho, but has transformed the mood at the club and appears to be unable to do any wrong.

“It’s fantastic to go through in the cup. It’s one of the hardest games you can get,” Solskjaer, whose start has eclipsed that of the great Matt Busby, said.

“Today we looked more like a proper team. We looked more structured. Today was a big step forward.

“It’s easy to get excited and talk about the future but we need to just keep working and think about the next game.”