Mata moved from Chelsea for £37.1 million and manager Moyes, who broke the club’s transfer record to sign him, revealed United had been working on the transfer for weeks.
“I am thrilled,” said Moyes. “I got wind a month or two ago it could be a possibility. I never believed we would pull it off.
Moyes added he had been cautious about United’s prospects in the winter transfer window but believes executive vice-chairman Ed Woodward, who was criticised after the club’s failed attempts to strengthen last summer, deserves credit for securing Mata’s signature.
“I have been saying that I didn’t think we would get a chance to do much business in January, I didn’t think the players we would be interested in would be available but when we got a sniff that Juan would be available we went after it right away and congratulations to the club and Ed Woodward for getting the deal done,” said Moyes.
Moyes only made one major signing in the summer, when he brought in Marouane Fellaini for £27.5 million from his former club Everton, but vowed United will be big spenders from now on.
He added: “There will be more players like Juan in the future. I have no doubt about that.”