After Florent Malouda had given the visitors an early lead, Saha got in front of John Terry to head David Moyes' side level and then hit a stunning 75th-minute winner to condemn Carlo Ancelotti's men to their first defeat in 14 games.
Moyes said: 'Saha should have scored four. If he'd done that I'd have given him a pat on the back. As it is, I have given him a slight nod to say well done.
Mobbed: Saha celebrates with Everton team-mates after his Goodison winner
Everton boss Moyes, however, was at least impressed with the way his top goalscorer troubled Terry throughout the match.
He said: 'Louis played really against him at Stamford Bridge and tonight I thought he did it again.
'I think John Terry was worried when the long ball dropped over the top and Louis took it on his chest. But John Terry is a top centre-half and if they don't want him I'll have him!
Setback: Ashley Cole tangles with Everton's Tim Cahill but later came off injured
'It's a terrific result and it just says the way we have been playing in the recent weeks and months.
To not have [Marouane] Fellaini and [Steven] Pienaar, who over the monthshave done really well for us, shows the players who have come in have donereally well.
'To go a goal behind and come back, I don't know how many teams dothat against Chelsea. We had to hang in because for 20 minutes Chelseawere fantastic.'
X-rated: Manchester United's Luis Nani (centre) was sent off for this challenge on Stiliyan Petrov
Chelsea will assess Ashley Cole on Thursday after the England left-back was forced off ater 57 minutes with an ankle injury.
Assistant manager Ray Wilkins said: 'He has taken quite a nasty knock. It wasn't a foul but it was a very strong challenge and he was slightly off balance.
'He has got a slight problem with his ankle but we will get back to Cobham andassess the situation.'
Flying finish: Diaby rises to power a header past Reina and snatch victory for Arsenal
Manchester United wasted the chance to go top after being held to a1-1 draw at Aston Villa, where United played for an hour with 10 menfollowing Nani's sending-off for a two-footed lunge at Stiliyan Petrov.Ryan Giggs, meanwhile, went to hospital with a suspected broken arm.
Arsenal strengthened their grip on third place with a 1-0 win over Liverpool at the Emirates.
John Terry given time off for bad behaviour: Chelsea defender will miss FA Cup tie in bid to save his marriage Everton 2 Chelsea 1: Terry pays the price as Saha pounces to net Goodison winner West Ham 2 Birmingham 0: Smiles better as Diamanti and Cole seal vital winAston Villa 1 Manchester Utd 1: Wayne Rooney can't work miracles after Nani horror showArsenal 1 Liverpool 0: Gunners banish the blues as Diaby revives title hopesWolves 1 Spurs 0: Jones' winner fires McCarthy's men out of bottom threeBlackburn 1 Hull 0: Phil Brown's fury at ref's 'nonsense' sending off of George Boateng CHELSEA FC