The 29-year-old Chile forward's transfer from Arsenal has proved one of the highest-profile deals of the January transfer window.

Mkhitaryan moved to Arsenal to push the deal through, and even though Sanchez's wages are reported to be on the higher end, Mourinho said he was pleased with the net gain for United.

"He was cheap, wasn't he? A free transfer, that's good," Mourinho laughed while speaking to reporters. "For that price it's fantastic.

"I think everybody thinks the same in this country. Everybody has to agree he's a fantastic player and it's a plus.

"We have a group of attacking players; Lingard, Lukaku on the bench, Zlatan, Martial at home. We have good quality in the group."

Mourinho also insisted that Sanchez's missed drugs test was "no one's mistake," after the player failed to inform drugs testers of his whereabouts on Monday, as his transfer was pushed through.

UK Anti-Doping officers were unable to locate him despite a trip to Arsenal's training ground, and on Friday Arsene Wenger admitted Arsenal should bear responsibility for not informing the authorities the Chile forward would not be at the club's Colney base.

Sanchez laid on two goals on his United debut as Mourinho's side overwhelmed Yeovil 4-0 at Huish Park on Friday night to move into the FA Cup fifth round, before Mourinho insisted the drugs test issue was an honest mix-up.

"I think Arsenal were very honest in the way they approached the situation,'' Mourinho said. "We all know we must tell the whereabouts, our players where they are 24 hours a day.

"Nobody knew where he was going to be, it was just a period of his transfer. So I think it's easily understandable, no one's mistake and just a consequence of the moment."