In a vintage performance, Mata scored a sensational match-winning brace and teed up Santos for the game-icing third in stoppage time.
But Mata's opening goal had to be seen to be believed.
The incredible Spanish maestro chipped City goalkeeper Patrick Beach from at least 40 yards to give Victory the lead in the 21st minute and deliver a goal that will go down in league history.
Nishan Velupillay pressed German Ferreyra and outmuscled the Argentinian, forcing the ball into the path of Mata, who spotted Beach off his line, shot first time and caressed it into the open goal.
The Champions League winner bowed to the crowd in celebration.
"It's been a very enjoyable night," Mata told Network 10.
"It was instinct. I saw that the goalkeeper was a bit out of his goal. Sometimes you try this and it goes to the corner kick but this one went in.
"I was actually waiting to check VAR for a possible free kick but I'm very happy they didn't rule it out."
It was Mata's first goal at AAMI Park and his second of three goals for the club, while the 37-year-old has a league-leading nine assists and looms as the Johnny Warren Medal favourite.
Victory's dominant performance (19 shots to six) sends them to fifth on 27 points while City (22) sit seventh.
"It was beautiful, wasn't it? That was outstanding. That's different class," Victory coach Arthur Diles said.
"And the second one's high level, and then the assist is high level.
"Top footballer helps us get the result tonight, and it's massive for him.
"I'm just really happy that he scored, because he's hit posts and crossbars, keepers have made fantastic saves on him.
"And, yes, he's given a great amount of assists. But I've been hoping, deep inside I'm thinking 'come on, you got to score more goals too, because you're worth it and you deserve it.' And tonight was beautiful to see that."
City young gun Marcus Younis burst down the right and teed up Max Caputo to head home the equaliser in the 32nd minute.
Medin Memeti should have put City in front in the 37th when Younis again broke free and squared a ball that begged to be tapped home.
But Memeti hit the tap-in poorly and Victory goalkeeper Jack Warshawsky brilliantly clawed the ball away.
But World Cup winner Mata wasn't done yet, receiving the ball from Matt Grimaldi he fizzed a scintillating strike from just outside the box past Beach for the winner in the 64th minute.
Mata then had one final say when he brilliantly released Santos down the left.
The Brazilian cut around Ferreyra and curled home Victory's third.
Mata received a standing ovation when he made way in the 91st minute.
"It can happen - he is who he is," City coach Aurelio Vidmar said.
"He's still a very, very good player.
"We definitely started poorly, very slowly, and the opposition were a much better team than us tonight. Simple as that."
Victory next host Adelaide on Friday night while City travel to face Auckland FC on Saturday.
City young gun Kavian Rahmani (lower back) was forced off in the 78th minute.
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