Arsenal snapped Emery up after the departure of long-time manager Arsene Wenger.
So far, Emery’s been a success in his first season as the Gunners are still involved in a highly-competitive top four race.
Watford, on the other hand, have been one of the surprise packages of the season so far.
Gracia has guided Watford to 10th place in the league but are in position to finish as high as seventh.
They’ve also made it to the FA Cup final where the Hornets will play Manchester City.
Emery spoke of Gracia’s involvement in him getting the Arsenal job, noting that the Watford boss was the first man he called in the “football world” about the job.
“When the possibility opened to sign here, the first coach, the first person in the football world I called was him,” Emery said.
“I asked some questions about the football here, the clubs, Arsenal, and he recommended to me that I come here.
“For example, we had dinner, their coaches and our coaches, one day in St Albans in September.
“We spoke about football here, English football and their experience because they were here six months before us.
“It was a good conversation about football because Javi Gracia is also a football man.
“They are my friends, not only Javi Gracia but also his assistants Zigor Aranalde and Inigo Arteaga.”
When the two sides last played, Arsenal came out on top 2-0 thanks to and own goal and a Mesut Ozil finish.
The Gunners need to win if they’re to keep up with the race for Champions League qualification.
They currently sit sixth in the league, but with two games in hand, they can reach third with victories in both those games.
If Arsenal don’t finish in the top four, they also have the fall-back of the Europa League – a competition that if they win, they automatically qualify for next season’s Champions League.