Aston Villa 2, Chelsea 0: Chelsea exposed by Villa's sense of purpose

Fourth place was probably not quite what Roman Abramovich had in mind when he told Jose Mourinho that Chelsea needed to reinvent themselves as the Premier League's most entertaining side. As the Russian made a sharp exit from the Villa Park directors' box yesterday he might even have been yearning for the days when Chelsea would grind the life out of these sort of matches and nick a win with relentless, unyielding force of will.

But if it is excitement Abramovich wants then this was it – although not the kind that £500m would usually buy you. In the closing stages Chelsea had John Terry as a centre-forward, Alex looking all over the place at centre-back and Juliano Belletti, the new £3.5m signing, absent without leave as Ashley Young raided the left wing. Exciting? Definitely. But not if you were supporting the team in the fluorescent yellow shirts.

The departure by Abramovich on 88 minutes, just moments after Gabriel Agbonlahor had drilled in Villa's second goal, was the kind of dramatic flourish to top a terrible afternoon for Chelsea. Perhaps that was why the club were so keen to reassure everyone that Abramovich was on his way to the dressing rooms and not trying to beat the traffic or – perish the thought – express his dismay at a performance that was woefully inadequate for his club's ambitions.

Whatever Abramovich did when he reached the dressing rooms, he would certainly not have been suggesting topping up the players' bonus scheme. This was a Chelsea team who looked hesitant at the back and, in conceding Zat Knight's goal from a corner, broke one of the immutable laws of Mourinho's three-year reign: thou shalt not lose thy man at set pieces. This is the new Chelsea – 4-3-3 on the pitch, slicked-back mobster hairstyle for Mourinho – and at first glance, neither looks that good. Unfortunately for Martin O'Neill, Chelsea's plight will overshadow a marvellous performance from his own team.

Villa played with the intensity you would expect of an O'Neill side, matching Chelsea's pace and energy and, in Young and Agbonlahor, had two of the game's most outstanding players.

While Shaun Wright-Phillips was excellent in the opening stages it was Young, who joins up with the England senior squad for the first time today, who looked the pick of the wide men. As centre-forward, John Carew gave Terry real trouble in the air and with the ball at his feet. The Norwegian striker is a handful but the England captain looked strangely out of sorts, his unease no doubt compounded by Alex's shaky first League start.

Didier Drogba hobbled off at the end, having contributed another spirited performance, but there was no denying that, in the absence of Frank Lampard, the goals have dried up for Chelsea.

Mourinho now has a lonely 10 days trying to figure out where it all went wrong for him in front of goal and, presumably, contemplating another unlikely possibility: recalling Andrei Shevchenko. The Ukrainian was overlooked again yesterday, without even a place on the bench, but he is surely a better bet than Claudio Pizarro, who was ineffective as a second-half substitute. Joe Cole has fallen out with his manager over his lack of games and after coming on yesterday hit the post.

If yesterday was about O'Neill's side finally looking the part, then it was also an occasion to remember for Knight, who scored on his debut, eight days after playing at Villa Park for Fulham and being substituted at half-time. It has not been the smoothest transition back to his hometown, not when you consider that his mother's house was raided by police on the morning of the day he was presented as a Villa player – his brother Carlos was questioned and bailed. But none of that will have mattered when he got above Drogba to nod in Gareth Barry's corner on 47 minutes.

By then, Chelsea were already struggling and Agbonlahor had missed two good chances to take the lead in the first half, the second a good save from Petr Cech when he spun away from Terry. The first half had ended with Villa in the ascendant: one ball into the box appeared to clip Terry's hand and Ashley Cole had to head off the line.

After Knight's goal, Mourinho threw everything he could muster at the home team. He wanted to send on Pizarro with such urgency that he shouted at John Obi Mikel when the midfielder did not come off quickly enough. Soon after that he called Joe Cole and Salomon Kalou off the bench, sacrificing Claude Makelele and Wright-Phillips but in the face of some serious pressure Villa were strong.

They employed a frantic, hustling game plan that closed down Chelsea at every turn. Young looked quick and direct against Belletti, the Brazilian from Barcelona making his debut at right-back, who faded towards the end. It was Terry who was sent back-pedalling as Young attacked the Chelsea box on 88 minutes. His cross was thumped by Agbonlahor past Cech. Cue Abramovich's exit, with a look of disdain on his face.

Goals: Knight (47) 1-0; Agbonlahor (88) 2-0.

Aston Villa (4-4-2): Carson; Mellberg, Knight, Laursen, Bouma; Agbonlahor, Reo-Coker, Barry, Young; Moore, Carew (Petrov, 78). Substitutes not used: Taylor (gk), Harewood, Gardner, Maloney.

Chelsea (4-3-3): Cech; Belletti, Terry, Alex, A Cole; Essien, Makelele (Kalou, 60), Mikel (Pizarro, 52); Wright-Phillips (J Cole, 60), Drogba, Malouda. Substitutes not used: Cudicini (gk), Ben-Haim.

Referee: M Clattenburg (Tyne & Wear).

Booked: Aston Villa Reo-Coker, Barry, Carew; Chelsea Drogba.

Man of the match: Young.

Attendance: 37,714.