Watch: Sanchez haunts Arsenal as United maintain perfect record under Solskjaer

Alexis Sanchez came back to haunt Arsenal as the Chilean opened the scoring in Manchester United's 3-1 FA Cup fourth-round win on Friday to maintain Ole Gunnar Solskjaer's 100 percent record as caretaker manager.

United's winning run under the Norwegian is now eight games in all competitions and his decision to make five changes was vindicated as both Sanchez and the returning Romelu Lukaku had a huge impact.

Lukaku set up both Sanchez's opener and Jesse Lingard's second for the visitors in a two-minute spell just after the half hour mark.

Pierre-Emerick Aubameyang reduced Arsenal's arrears just before half-time and the Gunners had plenty of chances to force a replay, but were denied by Sergio Romero as the rested David de Gea was not missed.

Eight minutes from time, United sealed a place in the last 16 when substitute Anthony Martial tucked home the rebound after Petr Cech could only parry Paul Pogba's initial effort.

Sanchez was roundly booed on his first visit to the Emirates since moving to Old Trafford just over a year ago after running down his contract at Arsenal into its final six months.

That move bagged the Chilean a highly lucrative deal, but Sanchez has failed to...