Doncaster 0-0 Cardiff
Away draw specialist Cardiff were held for the eighth time this season as Doncaster extended their unbeaten home league record to five games.
The first attempts on target came soon after the break as El-Hadji Diouf's shot was deflected past Cardiff's goal.
Aron Gunnarsson soon replied for Cardiff with a long-range drive that was comfortably saved by David Button.
Billy Sharp's appeal for a Doncaster penalty was waved away and the late home pressure came to nothing.
The result sees third-placed Cardiff lose ground on the top two, as Southampton and West Ham United opened a four-point lead with away victories.
But the Bluebirds were far from their best, troubled by an uneven playing surface and showing the effects of two consecutive away defeats in cup competitions.
Doncaster grew in confident as the second half progressed, and the results provides further encouragement as they aim to drag themselves out of the relegation places.
A tepid encounter finally came to life after the break, and Diouf should have broken the deadlock just a minute into the second half.
The former Liverpool forward showed great close control to dribble into area but his effort from 12 yards was deflected wide of the post by Cardiff goalkeeper David Marshall's fingertips.
Full-back James O'Connor headed over the crossbar as Doncaster began to turn the screw, and then Marshall rushed off his line to deny Sharp. The Doncaster striker appealed in vain for a penalty.
Cardiff lacked any cohesion in the final third, and their only effort in the final stages saw Button gathering Peter Whittingham's long-range drive without much alarm.
VIEWS FROM THE DRESSING ROOMS
Doncaster Rovers manager Dean Saunders told BBC Radio Sheffield:
"It was a tremendous performance. We made so many chances - we had enough to win three games and I thought we totally battered them from start to finish.
"How we've not come away with the three points is beyond me but the referee's not helped us either in certain instances and their keeper's made an unbelievable save from El-Hadji Diouf.
"The Billy goes through and I'm thinking goal but he just over runs it and then maybe looks like a penalty after that. But I can't complain, I thought the players were brilliant."
Bluebirds assistant manager David Kerslake told BBC Radio Wales:
"We were not at our best today, it just didn't go our way.
"They're always going to be a force here and they've won their last three at home - Southampton, Leicester, Barnsley - so it was a tough place to come.
"It [Tuesday's Carling Cup match at Crystal Palace] didn't help, especially with Doncaster not having a midweek game.
"A lot of this week has been about recovery. We're a fit group but it probably didn't help."