Bradford goalkeeper issues this warning to Sunderland ahead of League One clash

The Bantams sit 19th in the table, and have won just one of their five league games since David Hopkin's appointment last month.

However, Bradford are unbeaten in their last three league games and have kept back-to-back clean sheets in League One.

And O'Donnell believes his side will be a tough nut to crack when they face Jack Ross' promotion chasers tomorrow afternoon.

“We are progressing well and the last few games have been great to be a part of,” said O’Donnell, who has started every league game for the Bantams this campaign.

“The gaffer has come in and demanded a tightening up at the back, starting with clean sheets.

“We are beginning to deliver on that front and the results are coming for us."

Recent results certainly support O'Donnell's claims, and the Bantams look far more organised compared to when they conceded three goals at Blackpool in Hopkin's first game in charge a month ago.

Bradford have struggled at the other end of the pitch though, following the sale of Charlie Wyke in the summer.

But O'Donnell thinks improvements at the back will allow the team's offensive players to flourish.

“The gaffer knows we have players at the other end of the pitch who can go and score goals, so by offering a solid platform we give ourselves the best chance of winning," added O'Donnell.

“The Wimbledon victory was a real team effort. Everyone threw their bodies on the line. We wanted to get what was a crucial three points."

According to O'Donnell, Sunderland will pose the toughest test of the season in League One, and the Bradford keeper has issued a rallying cry to supporters.

“To get the result was great and everything feels very positive leading into the game against Sunderland," he added.

“We need the supporters to really get behind us on Saturday. It will give us a massive boost in what will be arguably our toughest game of the season.”