A much-changed Chelsea moved seven points behind Premier League leaders Liverpool after a 5-1 thrashing of bottom-side Southampton, who had captain Jack Stephens sent off for pulling Marc Cucurella's hair.
The Blues made seven changes for the trip to St Mary's and still produced a fine attacking display that will only increase talk of a potential title challenge this season as they moved second.
Three players brought in - Axel Disasi, Christopher Nkunku and Noni Madueke - all scored in the first half.
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Mike Dean reacts to Southampton red card.
Sky Sports Soccer Special pundit Mike Dean delivers his verdict on Southampton defender Jack Stephens' sending off
Disasi's seventh-minute header was, however, quickly cancelled out just four minutes later as Joe Aribo swept home past Chelsea goalkeeper Filip Jorgensen, who made his Premier League debut.
But Southampton's mistake-laden season continued as goalkeeper Joe Lumley's sloppy pass was cut out by Madueke who set up Nkunku to roll into an empty net in the 17th minute - a ninth Saints error leading to a goal in the Premier League this season.
Madueke then curled in a third in the 34th minute before Saints' night went from bad to worse five minutes later as skipper Stephens pulled Cucurella's hair at a Saints corner and was sent off for violent conduct following a VAR review at the pitchside monitor.
Chelsea then completely dominated proceedings and finally added a fourth through Cole Palmer's 77th-minute tap-in.
Substitute Jadon Sancho added a late fifth for his first Chelsea goal as Enzo Maresca's side made it seven games unbeaten in all competitions and next go to London rivals Tottenham on Sunday, live on Sky Sports.
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Southampton, meanwhile, are now seven points adrift from safety.
Story of the match in stats
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