Cardiff City and Swansea City flew out of the traps at the restart of the 2019/20 season.
The Swans thumped Middlesbrough 3-0 at the Riverside Stadium on Saturday while the Bluebirds beat high-flying Leeds United 2-0 in the Welsh capital on Sunday.
Other results ensured the race for the top six is wide open, too.
Preston conceded late on against Luton while Sheffield Wednesday scored at the death against Nottingham Forest.
It now means just three points separate seven sides who are battling it out for a play-off place.
Sixth-placed Preston are on 57 points with eight games to go, while Derby - who are 12th - are on 54 points.
And following what was a dramatic restart to the second-tier campaign, the odds have significantly changed on promotion.
Cardiff were 25/1 to go up last week, but have been slashed to 20/1 following their remarkable triumph over Marcelo Bielsa's side.
As for Swansea, they were at 22/1 to be promoted but have also been cut to 20/1.
Preston have gone from 10/1 to 12/1 while Blackburn and Millwall are both now 20/1 alongside the Swans and the Bluebirds.
Swansea return to action against Luton at the Liberty Stadium on Saturday while Cardiff take on Preston at Deepdale.
Latest Championship promotion odds
Leeds United - 1/25
West Brom - 1/20
Brentford - Evens
Fulham - 2/1
Nottingham Forest - 6/1
Preston - 12/1
Cardiff, Swansea, Blackburn and Millwall - 20/1
Bristol City - 33/1
Derby - 40/1
Queens Park Rangers - 200/1
Reading - 250/1
(Odds courtesy of The Pools, correct at time of publishing)
