Chelsea put in another strong showing in the league, dismantling a sorry Southampton by five goals to one.
Goals from Axel Disasi, Noni Madueke and Christopher Nkunku gave the Blues the lead at half-time, with Cole Palmer and substitute Jadon Sancho wrapping up the win after the break.
The Saints started stronger and found the net through Joe Aribo, but soon fell apart after captain Jack Stephens was sent off for violent conduct. Russell Martin's side remain bottom of the table, with just one win at home so far this season.
Chelsea were jubilant at full time and will be full of confidence ahead of a tough away trip to Tottenham Hotspur at the weekend.
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Story of the match
A midweek meeting meant some rotation for the Blues, and Maresca made seven changes - the likes of Christopher Nkunku, Axel Disasi and Tosin Adarabioyo all earned a starting spot, while Filip Jorgensen was given a first league start in goal.
For the Saints, three players missed out through suspension - Flynn Downes, Taylor Harwood-Bellis and former Chelsea academy player Tyler Dibling. Lesley Ugochukwu was also ineligible to play against his parent club.
It was the home side who started brighter with some early intensity and pressing - an early chance was dealt with well by Jorgensen, but the offside flag was raised quickly.
After soaking up the pressure well, Chelsea soon found their opener through Axel Disasi, who headed in a corner a few yards from the goal line.
The lead would only last a few minutes, as Kyle Walker-Peters set up Joe Aribo for the equaliser, after an error at the back by Enzo Fernandez.
The Saints will have been satisfied with their opening ten minutes, having troubled Chelsea with fast attacking moves and a positive spell of possession.
The match was an entertaining one regardless, and Chelsea had their lead back just six minutes later. Another needless mistake by goalkeeper Joe Lumley allowed Christopher Nkunku to shoot at an empty net, after Southampton had attempted to play out from the back.
Noni Madueke then had a good chance after cutting inside from the right, but Lumley redeemed himself with a strong save. Saints fans gave the goalkeeper some reassurance and motivation, as they let out a big cheer following a goal kick.
The nerves were eased with another good save - this time it was Cole Palmer's effort that was deflected onto the post by the Saints keeper. Felix had played a wonderful pass to Palmer, who took a brilliant touch to control the ball, but couldn't find the back of the net.
Chelsea were now up and running following some early pressure, with their travelling support in full voice. Russell Martin's possession-based system has attracted some critics, and the Southampton head coach knew his side needed to score next if they hoped to get a result out of the game.
Joao Felix often moved alongside Nkunku in a front two, with Palmer just behind them, as Chelsea targeted winning the ball back high and pinning their opponents into their own half.
The high pressure paid off, resulting in a third goal with ten minutes of the half still to play. Felix was free to play a pass to Madueke on the edge of the box, and the Chelsea winger curled an effort into the far corner to pile further misery onto their opponents.
Misery turned to despair as Jack Stephens was shown a straight red card for violent conduct, after tugging the hair of Marc Cucurella. There were jeers from the home support, who will have yearned for the half time whistle. Some took an early trip to the concourse, having seen enough.
Enzo Maresca saw his team dominate for large periods of the half, and will have wanted at least two or three more goals as reward for their hard work.
Some beautiful skill from Cole Palmer kicked off the second half. A turn and cross found Joao Felix free in the box, whose header was way off-target. Southampton needed to find a way nullify the Chelsea attack with only ten men.
It was attack after attack for the Blues - the closest of which was well defended by left-back Ryan Manning, putting in a challenge after Madueke attempted to pounce on a Cole Palmer rebound.
At the other end, Lumley did well to keep out a Madueke strike; the winger found well by Cucurella with a chipped pass. Chelsea were oozing with confidence and really should have extended their lead. It was becoming a game of attack versus defence, with the Saints forced to defend deep with ten.
Chelsea had their fourth through Cole Palmer, who turned in Nkunku's effort after a quick break through the middle of the pitch. It would be Palmer's final kick of the match, as he made way for Kiernan Dewsbury-Hall with ten minutes to play.
'We've got our Chelsea back' was sung by the Chelsea support as the Blues looked to wrap up a dominant away performance. Maresca had spoke in his press conference about the skepticism of Blues fans prior to his appointment, but after six months in charge, his name was being sung in positive chorus - to which he held his hands up in applause.
Jadon Sancho added a fifth from the bench with four minutes of regular time to play - a messy Saints defence allowed the winger to be played through, producing an emphatic finish at the near post.
Many home fans did not bother to sit through injury time; the stands looking bare as Chelsea saw out the rest of the match comfortably.
Player of the match - Noni Madueke
This was a dominant showing top to bottom from Enzo Maresca's side - not many players put a foot wrong.
A player who will be very content with their performance is Noni Madueke, who picked up a goal and assist in attack.
His strike was the pick of the bunch for the Blues, cutting inside and placing a well struck effort into the far corner.
Madueke's chance creation has also improved, showing great vision to pick out his teammates. He did well to set up Christopher Nkunku, restoring his team's lead in the first half.
There is real competition on the wing for Maresca's side - Pedro Neto and Jadon Sancho have both shone, but Madueke has shown that he can become a real star for Chelsea.