Aleksandar Mitrovic gave the Cottagers the lead on the hour mark, but that was a moment which turned the game on its head. Substitute Trezeguet notched a brace for Villa, and Ollie Watkins put the cherry on the cake in the 87th minute.
Story of the game
Coming into the match, Villa head coach Dean Smith made just one change to the side he fielded most recently before the international break, with Anwar El Ghazi coming in for Trezeguet on the right of attack. There was no place for club captain Jack Grealish in the matchday squad after he picked up a knock in training on Saturday.
Scott Parker, meanwhile, made four adjustments, with Kenny Tete replacing Antonee Robinson in defence, Bobby Decordova-Reid and Ruben Loftus-Cheek coming in for Ivan Cavaleiro and Andre-Frank Zambo Anguissa respectively in midfield, and Mitrovic taking Josh Maja's spot in leading the line for the visitors.
Villa started brightly. Matty Cash received the ball on the right flank and immediately whipped a cross into the area. It evaded the leap of Joachim Andersen and dropped straight at the feet of Watkins in the box, but the England international couldn't react quick enough and the chance fizzled out.
Moments later, Fulham surged right up the other end of the pitch. Ademola Lookman teased Cash before shifting the ball onto his right and feeding Mitrovic on the edge of the box. Unmarked, the striker turned on the spot and took aim at the near bottom corner, but Emi Martinez was equal to it.
Having scored five goals in three matches during the international break with Serbia, Mitrovic seemed to be in the mood for it today. He thought he'd won his side a penalty after a tussle with Tyrone Mings in the box but referee Andy Madley was unmoved. In the next phase of player, Decordova-Reid laid it off to the him on the edge of the area and his first-time shot drew a good diving save from Martinez.
But, truth be told, neither goalkeeper had much to do in the opening 35 minutes as play was generally locked in the middle of the park. This was set to be an attritional battle between two stubborn sides.
The best chance of a fairly barren spell came when Lookman fired in a vicious set-piece from about 25 yards out and right of goal. It soared through the mix in the middle and was met by Andersen at the back post but, on the full stretch, the Dane was unable to prod the ball home.
On the stroke of half-time, Villa thought they were presented with a golden opportunity to break the deadlock. Mario Lemina dwelled on the ball in his own box and appeared to fell Watkins as the striker moved in to tackle him, however a lengthy VAR check revealed the midfielder got a touch on the ball and Madley's decision was overturned.
Goalless at the break, and it felt as though the second-half had a lot of scope to open up.
Chances remained few and far between, though, and both sides were becoming increasingly frustrated. With 53 minutes on the clock, Decordova-Reid picked the ball up 35 yards from goal and, with little in the way of productive passing options available, decided to take aim, but the shot landed straight in Martinez's palms.
Fulham finally made a breakthrough right on the hour mark, capitalising on calamitous play from Villa. Ezri Konsa and Tyrone Mings dilly dallied in possession and the latter's attempted back-pass for Martinez was under-hit. Mitrovic ran onto hit, skipped past the goalkeeper and rolled the ball into the empty net to send the visiting contingent into rapturous celebrations.
They still had a long way to go yet, though, and Villa were likely to ramp up the pressure having fallen behind.
Keinan Davis was brought on to support a thus far isolated Watkins up front, but the hosts still struggled to make headway towards and into the Fulham box. Bertrand Traore attempted an audacious curling effort from way outside the box but, like Decordova-Reid's shot earlier, it was saved easily by Alphonse Areola who, to this point, had enjoyed a delightfully quiet afternoon.
But the opening did come for Villa, and they took it. Mings surged forward, exchanged a one-two with Matt Targett, and proceeded to atone for his earlier error with an inch-perfect driven cross into Trezeguet. The forward made no mistake from about 15 yards out, coolly slotting the ball into the bottom corner with Areola helpless to resist.
Moments later, John McGinn met a Targett set-piece at the back post and fired a vicious effort at goal, but it was just high and wide of the mark.
This match had been turned on its head. With 10 minutes remaining, Tosin Adarabioyo got caught in possession like Mings earlier and the defender was robbed by Davis. The striker bolted forward down the right and crossed to Trezeguet, unmarked on the other edge of the box, and the Egypt international took his chance with a powerful first-time finish.
It was ecstasy for Villa, disaster for Fulham. Three points, within reaching distance, had been blown away, and with less than 10 minutes to salvage anything at all from this match, the predicament of the visitors was unenviable.
And it got even worse for them. Villa regained possession high up the pitch and worked the ball to Traore out on the right. The winger left Ola Aina for dead and delivered a sumptuous cross into the box for Watkins to poke home. Game, set and match to a truly enthralling second-half at Villa Park.
Takeaways from the match
Villa show character after going a goal down
The word before the match was that Villa would miss Grealish, who was due to return today before a knock in training ruled him out. And that they did for two-thirds of the match; but they couldn't have responded any better to Fulham's goal on the hour mark.
Credit also to head coach Smith for his substitutions — Davis helped stretch the Fulham back line and open up space for Watkins, while Trezeguet's impact was tangible with his two goals.
Fulham have to start holding on
The mental scars of this defeat will not help Fulham's bid for survival with just seven games left to play. They were good value for a win today, and were set to earn it with 30 minutes remaining, but instead they leave empty-handed. This habit of profligacy is something they'll need to shake, and soon.
Parker will be pleased to see Mitrovic back amongst the goals, but much less so with what he witnessed at the other end of the pitch — it's the third match running in which defensive mistakes have cost his side, and moments such as these could prove crucial at the close of the campaign.
Aston Villa: Martinez; Cash, Konsa, Mings, Targett; Luiz (Ramsey 74'), McGinn; Traore, Sanson (Davis 68'), El Ghazi (Trezeguet 62'); Watkins.
Unused subs: Heaton, Elmohamady, Engels, Taylor, Nakamba, Barkley.
Fulham: Areola; Tete, Andersen, Adarabioyo, Aina; Reed, Lemina (Onomah 83'); Decordova-Reid, Loftus-Cheek (Maja 83'), Lookman (Cavaleiro 47'); Mitrovic.
Unused subs: Fabri, Ream, Kongolo, Robinson, Bryan, Anguissa.
Following victory here, Villa travel to champions Liverpool hoping for a repeat of their 7-2 trouncing of the Reds earlier in the season.