Chelsea 2-2 Blackburn
Blackburn maintained their impressive record at Stamford Bridge as they held Chelsea to a draw.
Rovers have not lost at Chelsea in the league for 20 years and a strike in each half by Andy Cole ruined the Londoners' perfect start to the season.
Adrian Mutu scored his second goal in as many games for Chelsea to get his new club back into the match on the stroke of half time.
And Jimmy Floyd Hasselbaink made no mistake from the penalty spot soon after Cole's second, but Chelsea could not find that elusive winner despite a late onslaught.
Blackburn made a dream start when Andy Cole fired them into the lead with 22 seconds on the clock.
The goal owed much to Marcel Desailly's elementary mistake.
22 secs: Cole shocks Chelsea with Blackburn's opener
45 mins: Mutu scores his second goal for Chelsea
58 mins: Cole taps in from close range
63 mins: Hasselbaink converts penalty to equalise for Chelsea
The normally unflappable Frenchman stumbled as he kept the ball in play on the touchline, allowing Matt Jansen to cross accurately for Cole to swivel and volley past Carlo Cudicini.
Blackburn, effectively the last club to have bought Premiership success from scratch when they won the title in 1995, continued to pressure their startled hosts.
But Chelsea are made of sterner stuff these days and steadily regrouped in an attempt to play their way back into the game.
The London club were unlucky not to restore parity midway through the first half, when Mutu's goal was harshly ruled out for offside.
The Romanian striker held his run to perfection as he waited for Geremi's pass.
When it arrived, Mutu finished superbly only for the fourth official to spoil Chelsea's celebrations with a raised flag.
But Mutu would not be denied a second time when he latched on to another through ball and showed excellent composure to round Brad Friedel and score with aplomb.
At the interval, Ranieri withdrew former Blackburn player Damien Duff, who had been a menace in the first half, and brought on Emmanuel Petit.
Another blunder in defence cost Chelsea once more and Cole added his second of the afternoon from five yards after Cudicini fumbled David Thompson's cross.
But back came Chelsea and they were level five minutes later when Hasselbaink converted his spot-kick after Lucas Neill handled Geremi's cross in the area.
Chelsea's latest acquisition, Hernan Crespo, made his Premiership debut late on as they pressed for the winner, but they could not find a way past Blackburn, who held on for a deserved point.
Chelsea: Cudicini, Johnson, Terry, Desailly, Bridge (Cole 84),
Veron, Lampard, Geremi, Duff (Petit 45), Mutu (Crespo 75),
Subs Not Used: Ambrosio, Gallas.
Blackburn: Friedel, Neill, Amoruso, Babbel, Gresko, Flitcroft,
Tugay (Martin Taylor 84), Reid (Johansson 72), Thompson, Cole,
Jansen (Gallagher 73).
Subs Not Used: Kelly, Grabbi.
Booked: Reid, Amoruso, Thompson, Flitcroft.
Referee: M Dean (Wirral).