Derby County have booked their place in the fourth round of the FA Cup after a last-gasp 1-0 victory over non-league Southport.

It appeared as though the Conference Premier team would earn a replay before Chris Martin struck from the penalty spot to earn the Championship side a place in Monday's draw.

Southport started well against their hosts, with Richard Brodie forcing a solid stop out of Kelle Roos, but the remainder of the first half was one-way traffic in favour of the Rams.

Craig Bryson struck the woodwork before Leon Best sent the rebound over the bar, while Simon Dawkins's goal-bound shot was deflected behind for a corner.

Goalkeeper David Raya Martin had to be alert to deny Paul Coutts before Ryan Shotton headed wide of the far post to allow Southport to see out the opening 45 minutes.

After the restart, Derby defensive duo Lee Naylor and Jake Buxton failed to find the target from inside the penalty area, before Southport almost found a shock opener through Brodie, but he could only head straight at Roos.

Just after the hour mark, Derby were fortunate to survive a goal-mouth scramble before they were denied by two excellent saves by Martin, who did well to keep out Bryson and Dawkins.

The match was becoming an end-to-end affair, with Southport having an increasing influence on the game, but defender Dominic Collins would have been disappointed not to do better when heading wide from six yards.

However, the final 20 minutes belonged to Derby, with Omar Mascarell having a long-range strike saved by Martin, and the goalkeeper followed that by parring away a header from Buxton.

Southport looked as if they had done enough to take the tie back to Haig Avenue, but Johnny Russell was brought down inside the box during stoppage time to give Derby a late chance of victory.

Martin made no mistake from the spot to register his 17th of the campaign and bring a huge sigh of relief from the home supporters.