Bradford City are on course to pull off another FA Cup upset having taken a 1-0 lead into half time against Sunderland.
The fourth-round conquerors of Chelsea took an early lead when striker Billy Clarke fired home via a deflection off Black Cats skipper John O'Shea.
Jon Stead's glancing header nearly extended Bradford's lead, before Ben Williams was called into action at the other end to keep out Adam Johnson's powerful drive.
Steven Fletcher then took a tumble in the box, but saw his appeal for a penalty waved away by referee Kevin Friend as the Premier League side continued to grow into the contest.
Sebastian Larsson was the next visiting player to try his luck on the end of a Danny Graham knockdown, getting away a shot which was deflected narrowly over the crossbar.
It was not all one-way traffic, however, as Clarke came close once more when he drove into the opposition box and forced a decent save out of Vito Mannone.
The pattern of the half had firmly been set, with both teams looking to create goalscoring chances. It was Sunderland who had the better of the final few minutes when Graham and Patrick van Aanholt both tested Williams, who managed to remain strong to preserve the Bradford's slender lead.
