Horndean boss Dave Carter lauded the 3-0 success at Winchester City as more than he could have dreamed of.
Goals from Mark Smith, Nathan Paxton and Harry Potter left the favourites shell-shocked as the Deans marched on in the FA Vase.
Carter felt all his players shone in the first round proper clash.
He said: ‘All the players stuck to their task and our game-plan worked better than we ever dreamed.
‘We played counter-attacking football and it paid off.
‘Every one of my players put in a fantastic shift.’
Horndean led at half-time through Smith’s well-taken goal, after Lewis Stockford put in a great through-ball.
In the opening 15 minutes of the second half, Horndean weathered sustained pressure before hitting on the break.
Paxton relieved the pressure when he headed in at the far post and substitute Potter killed the tie off, 10 minutes from the end.
Carter added: ‘Our goalkeeper Lyall Beazley didn’t have a save to make in the first half.
‘Winchester had a lot of possession but couldn’t break us down.’
There was no Vase joy for Fareham Town who lost 2-0 at fellow Wessex outfit Verwood Town.
Two first-half goals were enough to see the Reds’ bid for glory in the competition completely shattered.
United Services won 3-1 at Ringwood Town in the tie between the two Wessex League division one teams.
Meanwhile, in the Wessex League premier division, Moneyfields crushed 10-man Bournemouth Poppies 5-0 with a storming display.
Striker Steve Hutchings scored a hat-trick.
Jake Raine and Alfie Rutherford added further goals for the Dover Road side.
‘We looked very comfortable and the game was over by half-time when we had a 4-0 lead and they had a player sent off,’ said Moneyfields manager Miles Rutherford.
Petersfield Town came from behind twice but had to settle for a 2-2 draw against Hamworthy at Love Lane.
An own goal provided the first equaliser, with Warren Hunt heading in a second in the 64th minute.