Fernandes and Ighalo were two United's three additions during the January transfer window, along with Southend goalkeeper Nathan Bishop.
"We welcomed them both," Mata said. "Bruno is a very good player, we all know that, and a very nice guy also. We have been in contact a lot.
"He speaks Spanish mixed with Portuguese which is not very different, so he's a good guy and I think he's settling in very well.
"He's found his place in Manchester and also with the help of Fred, Andreas (Pereira) and Diogo (Dalot) he's enjoying it. They've helped him a lot.
"Hopefully he can help us in this second part of the season and I'm sure he will because he's a quality player."
Mata is also confident that Ighalo can make a positive impact for the rest of the season.
"Odion has experience of playing in the Premier League and hopefully he will score many goals for us from now until the end of the season," said the Spaniard.
"As the manager said, he's a good character as well and he's got a good personality which has fitted straight into the dressing room.
"The better he does, then the better for us - and I wish him all the best."