Hazard received the prestigious individual accolade at a glitzy ceremony in London on Sunday evening, and earned a special mention from Mata in his latest blog.
Mata also reserved praise for his good friend David de Gea, who missed out on the PFA Player of the Year and PFA Young Player of the Year awards but was named in the Team of the Year ahead of Chelsea's Thibaut Courtois.
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"I would like to congratulate my friend David de Gea for his inclusion in the PFA Team of the Year," Mata wrote. "It’s a reward for his great season and a recognition to his skills. And I also congratulate my friend Eden Hazard, who was named Player of the Year."
Hazard, 24, deservedly picked up the trophy following an excellent campaign with Chelsea, who are now five points away from winning their first Premier League title since 2010.
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Hazard delighted to claim top award
"I'm very happy," the Belgium international told reporters. "One day I want to be the best and what I did this season is play very well, Chelsea played very well.
"I don't know if I deserve to win but it is good for me. It is better to be voted by the players - they know everything about football.
"Personally I have played a good season, I have been there in the big games and I scored a lot of important goals, this is why I'm better this season."
Hazard won the PFA Player of the Year award ahead of Tottenham striker Harry Kane and United's De Gea, who finished in second and third place respectively.
Kane, however, sealed the PFA Young Player of the Year award following a remarkable season with Spurs.
Mata: United must bounce back
Earlier on Sunday, Mata and his Manchester United teammates were on the receiving end of a 3-0 hammering at the hands of Everton.
"I know that you are very disappointed after yesterday’s game. We do feel the same and I’m still sad as I write this, but the only thing we can do is to stick together and look ahead," Mata wrote. "For a team like us such a big score is not easy to take, but we have to put it aside to face the next games…
"They played their game very good, they were solid in defence and took almost every single chance they had to score. As I said before, we are in the final stage of the season and we must try to win each of the remaining games. The goal is to get four wins in the last four games of the Premier League."
United slipped down to fourth place after their surprise defeat at Goodison Park, with fifth-placed Liverpool now seven points behind the Red Devils.
Louis van Gaal's side will hope to bounce back by securing maximum points against West Brom this weekend. United then face tough matches against Crystal Palace, Arsenal and Hull City on the final day of the Premier League season.
Manchester United fans: are you worried you might not secure a top-four finish? Have your say in the comments below!