Chelsea came from behind for their second consecutive match to beat Sunderland 4-3 at the Stadium of Light. Poor defending from both teams led to the opening goals, before Eden Hazard turned his performance up a notch with two spectacular individual goals.
Phil Bardsley made sure that Hazard wouldn't hog all the headlines as he scored an own goal before redeeming himself at the right end just a few minutes later.
Here are six things we learned from Chelsea's performance in this dramatic midweek win.
Statistics taken from Four Four Two Statszone.
Chelsea supporters were thrilled when Frank Lampard's contract was renewed at the end of last season; however, few thought that he would feature so frequently at the age of 35. He no longer has the physical fitness to play 90 minutes twice a week and has been chasing shadows in several key games.
The problem for Jose Mourinho is working out if that matters when Lampard is still scoring and creating goals on the consistent basis that saw him surpass Bobby Tambling's record last season.
Mourinho may already have a few favourites in the Chelsea squad, but he does not have 11 of them. The uncertainty that surrounds places in the side is having a positive impact on a few of the players as they are forced to change their game and improve, but the constant changes make it difficult for the team to get into a rhythm.
Chelsea were lucky to take home all three points from the Stadium of Light, as misplaced passes and sloppy tackles got them into trouble.
They say three's a crowd, and in the case of Juan Mata, Eden Hazard and Oscar, the old cliche might be right.
Chelsea's talented attacking trio form great partnerships, but when the three of them are on the pitch, one always goes missing. This game was the perfect example of this phenomenon, as Hazard was on sensational form, yet when he lined up alongside Mata and Oscar against Southampton, he struggled to make the same impact.
However, if Oscar played in a deeper central midfield role as he has for Brazil, the three stars would have more balance and freedom to play to their strengths.
Four of Eden Hazard's five shots were on target as he ran the show. Two goals and an assist were complemented by five ball recoveries, and his passing was 91 percent accurate.
Hazard took on Oscar's all-purpose position and performed his role exceptionally.
For all of the invincibility of Mourinho's side in 2004-05, the mark of champions over the years has been the ability to win despite weaknesses.
Chelsea conceded several silly set pieces in dangerous areas and came unstuck against Sunderland. Were it not for Phil Bardsley's own goal, the Blues could have found themselves six points behind Arsenal. As it stands, they kept the gap at four points as the leaders prepare to face Everton and Manchester City in their next two fixtures.