It was a very poor return for Iffy Onoura who is now in charge at Gillingham as chants of "Iffy, Iffy, What's the score?" could be heard.
Swindon took the lead after only 4 minutes with a goal from Jon-Paul McGovern from close range to make it 1-0.
Swindon missed a couple more chances before making it 2-0 after 6 minutes when Simon Cox saw the 'keeper off his line and shot from just inside the box. The ball looked to be going over but dipped into the top of the net.
Gillingham never looked like scoring, and apart from a few corners Phil Smith had little to do all game.
Swindon had even more chances to score with a penalty appeal being turned down, and Billy Paynter coming close but hitting the ball wide when he should have scored.
Swindon went into the half time break only leading 2-0 when it could have been 5 or 6-0.
Simon Cox thought he'd made it 3-0 after 50 minutes with an over head kick which looked to have hit the post and gone in, but in had rolled in front of the goal and not crossed the line.
Billy Paynter made it 3-0 on 53 minutes with a close range goal.
Paynter then hit the bar, and a few seconds later from the same attack Swindon made it 4-0 with a header from Simon Cox on 65 minutes which saw a lot of the travelling fans from Kent leave early.
Billy Paynter made it 5-0 after 84 minutes when he was able to beat the defence and walk the ball around the Gillingham 'keeper and into the empty net.
With both Cox and Paynter on two goals each both tried to make it 6 goals for Swindon and get themselves a hat trick, but they ran out of time and the game ended with Swindon winning 5-0.
Overall a very good win for Swindon, with Gillingham playing very badly. If Swindon had taken all their chances then it could well have been into double figures with Swindon have 19 chances on goal compared with Gillingham's two. Poor Iffy Onoura tried to say out of the way as his side crashed. It seems the Gillingham chairman is now going to let their fans in for free for another Gillingham game to say sorry.