Ollie Watkins played the role of super sub as his second-half double enabled Aston Villa to fight back and stun Chelsea in a 2-1 away victory at Stamford Bridge.

A festive meeting between two prospective rivals for UEFA Champions League qualification was initially dominated by the home side, who went ahead late in the first half.

Reece James' wicked corner glanced in off the calf of Joao Pedro, and Unai Emery's side were arguably fortunate to make it to half-time only 1-0 down.

But the game changed when Emery introduced Watkins as part of a triple substitution in the 58th minute. He only needed five minutes to get Villa level, then headed home late on to spark wild celebrations among the travelling fans.

The victory moves third-place Villa back within three points of Premier League leaders Arsenal, who they face next in a huge clash at Emirates Stadium on Tuesday, while Chelsea are now three points adrift of the top four.

How the match unfolded

Chelsea spent the first half on the front foot. Enzo Fernandez curled just off target in the 18th minute, Joao Pedro's inventive flick was kept out by Emiliano Martinez following good work from Pedro Neto, and James sent a dangerous volley bobbling wide.

And James was the architect when Chelsea deservedly went ahead in the 37th minute, with his inswinging corner being touched home by Joao Pedro from virtually on the goalline.

Chelsea maintained the positive momentum in the second half, with John McGinn almost steering Cole Palmer's centre into his own net before Martinez made an acrobatic stop to prevent James' cross from flying in.

But Villa then created two big chances just after the hour mark. The first one for Boubacar Kamara was denied by Robert Sanchez, but from the second, the Chelsea goalkeeper’s save deflected back off Watkins and into the net.

And after his angled drive was repelled by Sanchez, Watkins gave the Chelsea goalkeeper no chance with a downward header from Youri Tielemans' 84th-minute corner to seal Villa's 11th straight win, equalling the club record.

Wasteful finishing gives Chelsea the festive blues

A dismal first-half showing gave Chelsea a mountain to climb away at Newcastle United prior to Christmas, but that was a summit they were able to scale as they fought back to draw 2-2.

It seems Enzo Maresca's men learned their lesson about starting quickly, but much like Newcastle last week, they were made to regret not making more of their first-half dominance.

Chelsea's control in midfield was aided by James stepping inside from right-back, and if not for the slightest of touches from Joao Pedro, who put Martinez under pressure beneath the crossbar, he would have had an 'Olimpico' goal from his curling corner.

The Blues were also unfortunate to see Alejandro Garnacho's tempting cross flick off Ian Maatsen's shoulder when Neto would have had a tap-in early in the second half.

Yet the game changed with Watkins' introduction, which forced Chelsea to drop deeper and granted Villa more space in midfield, with Morgan Rogers taking advantage – it was his delicious pass that helped create the equaliser.

And Maresca will be desperately disappointed by the way Malo Gusto and Moises Caicedo allowed Watkins to ghost in, unmarked, for his second goal, denying Chelsea even a point from a game they controlled for long periods.

The Blues will look to bounce back when they host AFC Bournemouth on Tuesday.

Watkins the hero in game of two halves

The confidence in Villa's camp could hardly have been much higher as they made the trip to London off the back of 10 straight wins in all competitions, with seven of those coming in the Premier League.

But Villa's trademark dynamism was lacking throughout a first half in which they failed to attempt a single shot – their first effort was a hopeful, 30-yard strike from Rogers that deflected comfortably wide in the 51st minute.

Soon afterwards, Emery introduced Amadou Onana, Jadon Sancho and Watkins in a triple substitution, and the arrival of the latter changed the game.

Without Watkins, Villa had lacked an outlet to stretch Chelsea's backline. But in his first major involvement, he released Kamara for a great chance. Less than two minutes later, Watkins got on the scoresheet from a similar run in behind, even if he was fortunate that his own saved attempt ricocheted off him.

Villa were then a changed team, with Rogers and Lucas Digne both going close from free-kicks either side of Watkins' towering header into the bottom-left corner.

Emery’s side could prove themselves to be true title contenders when they visit Arsenal next on Tuesday, although Matty Cash and Kamara will both be suspended after being booked in this game. (premierleague.com)