The Spaniard has come up against the Gunners three times since his departure from north London in 2019, with two of those coming in the Europa League semi-final when Villarreal knocked Arsenal out two years ago.
There is huge anticipation ahead of Saturday's clash at Villa Park, as Arsenal look to bring an end to what has been a remarkable run of results from Emery's side.
Villa have won 14 Premier League matches in a row on home soil, the most recent of those coming when they dominated Manchester City in midweek, and they have not been beaten at Villa Park since Arsenal came away with all three points in a dramatic match in February.
The Gunners go into the weekend two points clear at the top of the Premier League, but Villa will move to within just a point of them if they can pull of yet another memorable home win. Emery and his players are firmly in the hunt for European football, and the ambitions could become even loftier if their current form is extended into the new year.
Emery is not expecting a comfortably night on Saturday though, warning his players it will be their toughest test of the season, and he singled out Saka, who he handed an Arsenal debut to as a 17-year-old in 2018, as a major threat.
Saka has produced a string of superb performances this season, with eight goals and ten assists to his name already.
"They [Arsenal] have always had good players in their academy and Saka was one very good example," Emery said.
"His development was because he had very good coaches in the academy and I helped him and he’s developing a lot under Mikel Arteta. He’s a very good player and he’s a humble person, and I’m very happy for him as a player."
Emery had just one full season in charge at Arsenal, leading them to the Europa League final but falling away late in the Premier League campaign to miss out on Champions League qualification.
He was sacked in November of the following season, with Mikel Arteta appointed as his replacement, and the current Arsenal boss was asked in his pre-match press conference on Friday whether Emery was simply in charge at the wrong time.
Arteta said: "I don’t know, the timing was as it was. I think he still did some very good things here, but it’s not for me to judge that."