Yeovil Town suffered defeat in their first home game in the second tier, while last season's Premier League duo Reading and Queens Park Rangers both drew away from home.
Brighton & Hove Albion, Charlton Athletic, Millwall and Sheffield Wednesday, meanwhile, all slipped to second successive defeats in the league.
Troy Deeney scored a second-half hat-trick, and Gabriele Angella netted twice, as Watford thrashed Bournemouth 6-1 at Vicarage Road.
Darius Henderson scored a last-minute winner as Nottingham Forest won 1-0 at Ewood Park to leave Blackburn waiting for a first win of the season amid reports manager Gary Bowyer is already under pressure.
Blackpool were also last-gasp winners as Scott Wiseman's own goal at Bloomfield Road condemned Barnsley to back-to-back defeats.
Huddersfield Town picked up a first point of the season after James Vaughan's 35th minute opener was cancelled out by Junior Hoilett three minutes later in a 1-1 home draw with QPR.
Nick Blackman's 51st minute penalty earned Reading a point at the Reebok Stadium as Bolton Wanderers drew 1-1 for the second week in a row.
Strike duo Danny Ings and Sam Vokes scored in the first half as Burnley claimed a first win of the season after beating Sheffield Wednesday 2-1 at Hillsborough.
Lukas Jutkiewicz's 72nd minute goal secured Middlesbrough a first three points of the campaign after a 1-0 triumph at Charlton.
Chris Martin scored a goal in each half as Derby County came from behind to record an impressive 2-1 success at Brighton.
Dan Burn returned to haunt Yeovil as the defender's deflected header early in the second half gave Birmingham a 1-0 win at Huish Park.
A spell of three goals in the space of 20 second-half minutes got Ipswich Town up and running for the season after a 3-0 home win over Millwall.