Leicester boss Enzo Maresca expects plenty more twists in the Championship promotion race.
The Foxes suffered a wobble in their bid for an instant return to the Premier League after a stunning Ryan Longman strike condemned them to a 1-0 defeat at struggling Millwall.
Back-to-back wins had reignited their promotion bid and lifted them back to the top of the pile.
But, while Leeds could only pick up a point at home to Sunderland and stay second, third-placed Ipswich can climb above both if they beat Watford on Wednesday.
“It was a tough night, in the first half we struggled on the ball, we were not clean,” said Maresca.
“They defended very well. We expected in the second half to find more space but they scored a fantastic goal.
“Now is not the time to think too much. Tonight is gone.
“The last games are more or less similar for all the teams. Clubs are trying to survive or go up, the intensity is higher. It's a problem for us, but for every club.
“If you watch the table yesterday, and tonight, and in two days, you'd go crazy. We have to go game by game.”
The goal arrived on the hour after Wout Faes lost the ball in midfield and Billy Mitchell sent Longman scampering away down the left.
The on-loan Hull winger cut inside Harry Winks before curling a spectacular 25-yard effort past Foxes goalkeeper Mads Hermansen and in off the underside of the crossbar.
Kelechi Iheanacho had the chance to rescue a point in stoppage time but his header was cleared from under the crossbar by Mitchell.
The Lions were in need of the points for different reasons and battled to a first win in five matches to go four points clear of the relegation zone.
Lions boss Neil Harris said: “Firstly, it's so Millwall-like to lose to Rotherham and Huddersfield, both in the last minute, and then beat the league leaders.
“That's what this club does. Not just this group. The last 30 years of Millwall Football Club.
“We scored a goal that would win any game at this level. I thought it was an excellent Millwall performance. To play against arguably the best team in the league and limit them to very little was so impressive.
“We're moving in the right direction. What I'm seeing in the group is a lot of positives.”
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