Evans headed PNE level at the Riverside Stadium, with Emil Riis going on to score the winner soon after.
North End head coach admitted putting the Welshman on as a 53rd-minute substitute meant he played for a bit longer than planned.
However, Evans’ fitness impressed him, the striker having done a lot of work to get back to those levels after three months out with plantar fasciitis – an injury to the tissue on the soles of his feet.
McAvoy said: “Ched had been biting at me to get back in the squad, he kept saying, ‘I’m ready to go, I’m ready’.
“The medical and fitness staff have done a lot of fantastic work to get him to where he is now.
“Although he hasn’t done a lot of contact stuff in training, he has worked extremely hard to get his fitness levels to where they are.
“You saw the impact he had at Middlesbrough, and it’s not just on the pitch. Off it, Ched is a big character and we’re delighted to have him back in the group.
Before the Middlesbrough game, 32-year-old Evans had not played since August 17.
His foot issues started in pre-season and the injury really flared-up soon after the start of the season.
Said McAvoy: “This type of injury can last quite a while.
“Jonny Evans at Leicester has had the same injury and he’s back playing now.
“It takes a bit of time to get right and isn’t really an injury you can rush back from.
“When he first came on in the Middlesbrough game his running style gave the impression he was still carrying it a bit.
“But after five or 10 minutes he got himself going and he became a real handful.
“The leap and the header for the goal were magnificent and towards the end he managed the game well, taking a lot of pressure off us.”
North End’s comeback was assisted by McAvoy changing to 4-3-3 for the last 20 minutes after Daniel Johnson and Scott Sinclair joined Evans in the action from the bench.
“We stayed in the game at 1-0 and when Ched came on the ball started to stick more at that end,” McAvoy said.
“When we got the equaliser I thought we could go on and get another to win the game.
“I could have been happy with 1-1 and easily reverted to three at the back.
“Middlesbrough put the big lad Uche Ikpeazu on but we needed to win the game.
“That is what the task is, that is what we try to do.
“We need to get a lot more consistency to our results, it’s been win and lose recently and we need more wins.”