Retour
While Bradford City were dismantling Marine 7-0 over at Valley Parade, things were much more tense a few miles away at Nethermoor.
But Guiseley got the job done against a team from two divisions above them, thanks to a last-gasp penalty from Jordan Thewlis.
The hosts had their chances in the first half, Elliot Owen going close twice while Jack Emmett had a header cleared off the line.
A medical incident in the crowd meant the second half kicked off nearly 25 minutes late, and the game looked destined for an extremely late finish, as extra-time and penalties loomed.
But Guiseley found the strength for one last push and after Kyle White was kept out by a brilliant save from the Sutton keeper, they eventually had their moment of glory.
With a minute of second half stoppage time remaining, Thewlis won his side a penalty after being brought down in the box.
He dusted himself down to take the spot kick and he slotted the ball home to spark bedlam inside Nethermoor.
Guiseley will now be involved in tomorrow night’s second round draw alongside the Bantams.