Matic joined Manchester United from champions Chelsea in July for a fee of around £40million.
The Serbia international had helped the Blues to two league titles in three years after Jose Mourinho re-signed him from Benfica in 2014.
Mourinho, now at Old Trafford, has reunited himself with the 29-year-old, with Chelsea signing Tiemoue Bakayoko from Monaco as his replacement.
Pardew believes Mourinho will be over the moon with the signing because Matic is the best defensive midfielder the Premier League has seen.
And he reckons Paul Pogba will benefit from having him in the side.
“Pogba had to protect last year, he had to fill that hole but Matic just does it automatically,” Pardew said on Sky Sports.
“He’s the best that I’ve ever seen in the Premier League, in the last sort of seven or eight years anyway.
“When he’s played at Chelsea he’s been terrific, he was terrific at Benfica.
“Now he’s come here to do the job, I was very, very surprised that Chelsea have let him go.
“For whatever reason he is here, I think Jose must be falling over himself!”
