The 24-year-old was in imperious mood at Fulham last weekend as he struck twice to take his goal tally to five in nine league games.
"We know he's a really vital player for us and let's hope this excellent form continues," Mirallas told evertontv. "When it comes to the big vital games he's always there and we can rely on him to come up with a big performance.
"You only had to look at his second goal at Fulham on Saturday - he basically made it and scored it all on his own. It was a fantastic effort.
"It's four years now that he's been here and I think in that time you can see how much he's come on as a player, he's really made good progress. He's about to turn 25, so I think he's still got plenty of chance to improve even more."