Barnsley 0-0 Wolverhampton Wanderers
Championship leaders Wolves stretched their unbeaten run in league and cup to 14 games but were held to a goalless draw at Barnsley.
Helder Costa and Diogo Jota had the ball in the net for the visitors, only to be denied by offside flags.
And Jota also struck the crossbar with a fierce second-half drive against a determined Barnsley side.
Adam Hammill and Stevie Mallan had Barnsley's best efforts, but were denied by keeper John Ruddy.
The draw meant Wolves' lead at the top was cut to 10 points by Derby, who won 3-0 at Birmingham City, while Barnsley remained 19th, three points clear of the relegation places.
Paul Heckingbottom's Tykes have now won only once in 13 games, but a point was a satisfactory outcome and new signing Kieffer Moore was given his first run-out as a substitute after the interval.
And they had a chance to snatch victory late on when George Moncur fired with a snapshot from the edge of the area.
Jota carried the biggest threat for Wolves and, after slotting home from Costa's cutback, only to be denied by the linesman, he thumped the woodwork following a quick break and then somehow cleared the bar from two yards when he slid in to meet Ivan Cavaleiro's cross.
Barnsley manager Paul Heckingbottom told BBC Radio Sheffield:
"I'm pleased with the performance and I enjoyed the game if I'm honest.
"I thought it was really competitive, really high tempo, I thought we played well and you can see why they're top of the league.
"We've had four clean sheets in the last six or seven in the league, which is the right way to go about it."
Wolves head coach Nuno Espirito Santo said:
"If there was going to be a winner it would be Wolves. We didn't concede anything to Barnsley.
"Teams are trying to adapt their shape to our idea. That was not the case of Barnsley. Paul knows what he's doing. There are a lot of teams adapting but that makes you grow.
"It's a challenge knowing that you have to find solutions - grow and play better."