Leicester moved eight points clear at the top of the Championship as James Justin's early goal beat Sunderland 1-0 on Tuesday.
The Foxes have taken 36 from a possible 39 points in their opening 13 games back in the second tier, but already look set to return to the Premier League next season.
Justin rose highest to head home Kiernan Dewsbury-Hall's corner after 12 minutes to secure an eighth consecutive win for Enzo Maresca's men.
After a promising start to the season, Sunderland have now lost their last three games to slip to ninth, one point off the playoff places.
Middlesbrough's charge up the table continued as Michael Carrick's side won 2-1 at Norwich for a sixth straight win.
Sam Greenwood and Sammy Silvera were on target for the visitors at Carrow Road before Jonathan Rowe pulled a goal back at the death for the Canaries.
Boro climb up to seventh, outside the playoff places only on goal difference, despite failing to win in their first seven games of the season.
Cardiff did move into the top six thanks to their 4-0 thrashing of Huddersfield.
Callum Robinson, Dimitrios Goutas, Yakou Meite and Perry Ng were on target for the Bluebirds.
West Brom went fifth by beating QPR 2-0.
Watford were 1-0 winners at Swansea, while Blackburn beat Millwall 2-1.