Jose Mourinho has opened up on why Manchester United battled so hard to sign Alexis Sanchez ahead of Sunday's Old Trafford showdown with Arsenal.
The Chilean looks set to line up against his former club, having switched in January as part of a swap deal with Henrikh Mkhitaryan.
Sanchez has been criticised for some lacklustre performances this season, but looks back to his best having recently inspired United's comeback to beat neighbours City in the Premier League and Tottenham in the FA Cup semi-final.
"We fought to have him here and I was, since day one, sure that he was the right player," said Mourinho.
"Not just by the typical football qualities, but also by his mentality, and we needed that.
"I don't like the January market but it was now or never. We needed a little bit more experience, we needed a little bit more mental aggressiveness, and I knew that sooner or later, we're coming [improving as a team]."
It will be an emotional occasion on Sunday as Arsene Wenger takes on United for the last time as Gunners boss, as well as Sanchez going up against his old team-mates.
"We need seven points and we have a cup final to play, and can he help us, I hope so," Mourinho added.
"If we can have good Alexis until the end of the season, then better for us.
"Next season, after pre-season, after being comfortable and adapted, he's going to be great for us."