Match ends, Coventry City 1, Sunderland 0.
Coventry City went top of League One as Matt Godden's early goal beat promotion rivals Sunderland at St Andrew's.
Godden struck inside two minutes to extend Coventry's unbeaten run to 13 league matches and establish a two-point cushion above Rotherham United.
Charlie Wyke and Tom Flanagan wasted the best chances for Sunderland, who stay fifth, four points off Rotherham.
The Black Cats thought they had levelled but Max Power's strike was deflected in by an offside Luke O'Nien.
Referee Michael Salisbury and his linesman took their time to determine that O'Nien had got a touch to his fellow midfielder's 75th-minute strike.
Wyke had spurned a great chance to bring Sunderland level minutes earlier, sending a tame free header straight at Sky Blues keeper Marko Marosi from Chris Maguire's cross.
After the recalled Jamie Allen's delightful through ball had set up City top scorer Godden to drive home his 14th of the season, Sunderland's clearest opportunities came shortly after the goal.
Wyke fired an instinctive effort narrowly off target from 20 yards and Flanagan volleyed wildly over when a free-kick picked him out completely unmarked at the far post.
Godden sent a one-on-one chance wide late on that could have sealed it but Coventry, who now have the current longest unbeaten run in English league football (after losses for Liverpool and Gillingham on Saturday), still leapfrogged Rotherham to the summit.
City, who last topped the League One table in mid-September, also have a game in hand on the second-placed Millers, ahead of next Saturday's trip to ninth-placed Ipswich Town.
Another good gate in Birmingham
The gate of 10,055 at St Andrew was the first time Coventry have reached five figures in a league game at their latest temporary home.
It tops this term's previous league best of 8,990, who were here on Tuesday night for the visit of Rotherham. But this time the Railway Stand was swelled by 3,323 visiting fans.
Coventry are attracting average home league crowds of 6,677 this season to Birmingham.
That is well down on last season's Ricoh Arena average of 12,363 - but it is three times better than the gates they had in their season at Northampton, in 2013-14, when they averaged only 2,287 at Sixfields.
The overall biggest 'home' gate they have had at St Andrew's was 21,193 for the original FA Cup tenants v landlords fourth-round tie with Birmingham City, which was actually the Sky Blues' 'home game'.
Coventry City boss Mark Robins:
"We just have to do what we are doing. We have Ipswich next and we will need to keep playing well. There are a lot of tough games to come, there are no easy games.
"We had a brilliant start, one we needed against a strong powerful team who are full of confidence.
"To score a goal of that quality and keep a clean sheet is pleasing. We had to defend well at times.
"We knew their 'goal' was offside. We thankfully don't have VAR, but the officials have got the right decision."
Sunderland manager Phil Parkinson:
"It is frustrating to have got off to the start that we did. There was a lack of communication in and around our box and we were punished.
"It was always going to be a tough game and, when you give a team a goal start so early, it gives them a boost.
"The offside goal was the right decision. I can't complain at the call.
"The effort was there but we were just a bit frantic and lacked quality."
- 1MarosiBooked at 31mins
- 8AllenSubstituted forBakayokoat 79'minutes
- 24GoddenSubstituted forShipleyat 90+3'minutes
- 4WillisSubstituted forSemenyoat 78'minutes
- 33HumeSubstituted forLaffertyat 69'minutes
- Michael Salisbury
- Shots on Target
Second Half ends, Coventry City 1, Sunderland 0.
Foul by Charlie Wyke (Sunderland).
Liam Kelly (Coventry City) wins a free kick in the attacking half.
Substitution, Coventry City. Jordan Shipley replaces Matt Godden.
Foul by Antoine Semenyo (Sunderland).
Callum O'Hare (Coventry City) wins a free kick on the left wing.
Attempt blocked. Charlie Wyke (Sunderland) right footed shot from the centre of the box is blocked. Assisted by Luke O'Nien.
Max Power (Sunderland) wins a free kick in the defensive half.
Foul by Liam Kelly (Coventry City).
Foul by Kyle Lafferty (Sunderland).
Liam Walsh (Coventry City) wins a free kick in the attacking half.
Attempt missed. Matt Godden (Coventry City) right footed shot from outside the box is close, but misses to the left. Assisted by Sam McCallum following a fast break.
Attempt blocked. Lynden Gooch (Sunderland) left footed shot from outside the box is blocked. Assisted by Chris Maguire.
Corner, Sunderland. Conceded by Dominic Hyam.
George Dobson (Sunderland) wins a free kick in the defensive half.
Foul by Matt Godden (Coventry City).
Substitution, Coventry City. Amadou Bakayoko replaces Jamie Allen.
Foul by Antoine Semenyo (Sunderland).
Sam McCallum (Coventry City) wins a free kick on the left wing.