Roarie Deacon was the hero for Sutton as his last-gasp goal snatched a 2-1 win against League Two strugglers Cheltenham and a place in the third round of the FA Cup.
The National League side have cup pedigree having knocked then top-flight club Coventry out of the competition in 1989, and they will now be in the draw with the big boys once again after beating the Robins.
Cheltenham opened the scoring in the 35th minute when a James Dayton free kick picked out Danny Wright and he tapped home.
But Sutton drew level at the start of the second half when new signing Matt Tubbs slotted home from 10 yards and there was late, late drama when Deacon thumped home in the sixth minute of time added on to snatch another famous victory.
Scott Kashket scored a hat trick as League Two side Wycombe crushed League One strugglers Chesterfield 5-0 at the Proact Stadium.
The emphatic result was perhaps less surprising given the Chairboys had won their last four games, but the Spireites -- 22nd in the third tier -- went into the match on the back of successive 3-2 wins.
Wycombe took the lead in the 21st minute when skipper Paul Hayes glanced a header past goalkeeper Ryan Fulton from Kashket's cross.
Kashket doubled the Chairboys' lead three minutes later and kept his cool one-on-one to add a third in the 70th minute, shortly after Chesterfield's Jon Nolan had seen red for a lunge on Dominic Gape.
Stewart scored a fourth shortly afterwards and Kashket's fifth goal in two games sealed a convincing victory for Gareth Ainsworth's rapidly improving side.
Luton were forced to come from behind before beating Solihull Moors 6-2.
The Hatters, who had knocked Championship side Aston Villa out of the EFL Cup earlier in the season, were at risk of being on the receiving end this time around as they found themselves two goals down at the break.
However, they came out fighting after the interval and four goals in 12 minutes shortly after the restart and two further strikes at the death eased the League Two promotion hopefuls into the next round.
National League side Solihull took the lead after just five minutes as midfielder Jamey Osborne let fly with a shot into the top-right corner. And the same player increased Moors' lead in the 35th minute with a low drive from the edge of the box.
Luton pulled a goal back in the 51st minute when in-form striker Danny Hylton raced onto a pinpoint ball over the top from Jack Marriott and calmly placed the ball past the keeper.
It was all square three minutes later when Johnny Mullins curled the ball into the bottom corner and the turnaround was complete five minutes after that as Stephen O'Donnell coolly converted another Marriott pass.
The impressive Marriott added a fourth in the 63rd minute, O'Donnell's second of the game made it five and Marriott capped a fine second-half display with a sixth in stoppage time.
Elsewhere, Newport held on for a goalless draw at Plymouth after Sean Rigg had been sent off in the 23rd minute for a poor challenge on home striker Jake Jervis.
Karl Robinson's first game in charge of Charlton ended in a goalless draw against his former club MK Dons, while Jamille Matt's early goal was enough for Blackpool to see off Brackley 1-0.
League Two leaders Carlisle slipped to a rare home defeat as League One high-fliers Rochdale claimed a 2-0 victory.
Steven Davies' deflected half-volley put Dale in front, with substitute Nathaniel Mendez-Laing sealing victory in time added on.
Shrewsbury played out a 0-0 draw at home to Fleetwood.