Veteran forward Gareth Taylor scored a last-gasp winner to break the hearts of brave Lowestoft Town in a 1-0 victory at the Racecourse Ground.
Former Sheffield United striker Taylor popped up with an 89th-minute header to finally break the Trawler Boys' rearguard action.
Visiting goalkeeper Andy Reynolds had produced a man-of-the-match display to keep the Dragons out, but just as a replay looked likely, the 36-year-old struck.
Minnows Lowestoft found themselves under pressure for much of the first half and Lamine Sakho almost drew first blood in the 18th minute but his mazy run was halted by centre-half Gary Holt.
Taylor was the next to go close shortly afterwards but his strike with the outside of his boot was expertly turned behind by Reynolds.
Jamie McCluskey's first-time strike then threatened for Wrexham but Adam Smith almost caught the home side napping as his dipping 35-yard strike just cleared Chris Maxwell's crossbar.
Wrexham continued to lay siege to the visitors` goal after the break with McCluskey firing a shot into the side-netting.
Wes Baynes then saw a venomous 20-yard free-kick deflected wide on the hour before an unmarked Taylor had his header saved by Reynolds after 76 minutes.
But Taylor quickly turned from zero to hero as his header from Mark Jones' cross broke Lowestoft hearts just a minute before the final whistle.