Eyebrows were raised when Aston Villa paid a club-record £28 million for Ollie Watkins from Championship club Brentford. A hat-trick against Liverpool and two goals in this stunning victory over Arsenal later and the striker is already looking like a bargain.
Having also netted a penalty in the defeat by Southampton, Watkins now has six Premier League goals in seven games for Villa and he outshone Pierre-Emerick Aubameyang and Alexandre Lacazette at the Emirates.
It was a quick second-half double from Watkins that effectively sealed a fifth win of the season for Villa and yet the result was about so much more than just the in-form 24-year-old.
Captain Jack Grealish was imperious and offered Villa the kind of craft and creativity that Arsenal so lacked.
Honourable mentions should also go to midfield trio Ross Barkley, John McGinn and Douglas Luiz who bossed Mohamed Elneny, Thomas Partey, who suffered a thigh injury, and substitute Dani Ceballos.
Arsenal manager Mikel Arteta will be wondering how the same team that had beaten Manchester United could be so easily dispatched and the Gunners remain a puzzle, taking two steps backwards after making such a positive stride forwards at Old Trafford.
Arteta's team had gone into the game with the meanest defence in the Premier League, having conceded only seven goals. But it took Villa just 47 seconds to get through their back line, when the visitors thought they had added an eighth to Arsenal's goals against column.
Matt Targett floated the ball over the top for Grealish, who picked out McGinn and the Scotsman smashed an unstoppable shot into the top corner of the net.
As Villa celebrated and Arsenal trudged back to the centre circle, there appeared no immediate hint within the stadium that the goal might be ruled out.
But kick-off was delayed for a Var check against Barkley and referee Martin Atkinson eventually went over to the pitchside monitor and ruled the midfielder had been stood offside in the eyeline of goalkeeper Bernd Leno.
Villa's second goal did count, although it was eventually ruled as an own-goal by Bukayo Saka, who had tried to deny Trezeguet a simple tap in.
Having weathered some sustained Arsenal pressure, during which McGinn had almost gifted Thomas Partey a goal and Willian fired over, it was in the 25th minute that Villa took the lead.
Targett and Grealish were involved again, as the pair, together with Barkley, patiently held on to the ball down the left, looking for a gap.
Arsenal's defence switched off, allowing Barkley to find Targett and his low cross looked to have been diverted into the net by Trezeguet.
The Egyptian certainly celebrated like he had opened the scoring, but replays showed that it was Saka who touched the ball into his own net just in front of Villa's winger.
Villa goalkeeper Emiliano Martinez was back at his old club and the 28-year-old had done well to stop Partey capitalising on McGinn's early mistake.
Martinez looked set to be beaten four minutes before the break, when Kieran Tierney swung over a dangerous cross but Alexandre Lacazette, arriving unmarked, headed wastefully over the crossbar.
Arteta made an enforced change at the break, sending on Ceballos to replace Partey, but it was Leno who was called into action first in the second half.
Grealish dribbled his way into the penalty area, before cutting the ball back for Barkley. He then found Trezeguet on the right, whose shot from a tight angle was palmed out by Leno.
Both Ceballos and Rob Holding should have done better than to shoot wide for the hosts. The Spaniard curled his effort the wrong side of the post after a Willian free-kick had been worked out to him, while Holding missed the target after being picked out by Gabriel, who had been up for a corner.
Arteta decided to gamble with 25 minutes remaining, using his two remaining substitutes to send on Nicolas Pepe and Eddie Nketiah. Pepe had Martinez diving cross his goal with a fierce left-foot drive that was only just off target.
But it was Villa and Watkins who made a stunning impact with two brilliant goals in four minutes. Luiz played a wonderful pass over the Arsenal defence and Barkley's volleyed cross was headed into the net by Watkins.
That two-goal advantage almost became three immediately, as Trezeguet won the ball back from the Arsenal kick-off and played in Barkley, who brilliantly found Grealish. The midfielder's shot was cleared off the line by Ceballos, but Villa got their third goal in the 76th minute.
Martinez plucked an aimless cross out of the air and rolled the ball to Grealish, who ran almost the length of the pitch before slipping in Watkins and the striker kept his cool to find the back of the net.
Arsenal had no response as Villa ended their two-game losing run and have now netted 10 goals in matches against Liverpool and Arsenal in this unpredictable, crazy season.
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