Averaging over five goals a match in their last four games, the in-form Wessex League side were just too strong for a Fleet side, still fighting their way out of a poor run of form.
Mick Catlin's side, currently holders of the Russell Cotes Cup, played brightly in patches, but struggled to deal with the Winchester strike pair of Andy Forbes and Ian Mancey, who have already scored 55 goals between them so far this season.
Once again there were significant absentees in the Fleet line-up, Striker Steve Whitcher was cup-tied; Richard Mealey and Ed Hare were unavailable, and Nick Clark, Brian Wood and Jamie Proctor were still off with injuries. There was though a welcome return for former skipper, Craig Anstey, back after a 3-match suspension.
The Fleet goal was under pressure right from the off, with former Fleet striker, Mancey proving a handful for the Fleet defence.
It was Mancey who opened the scoring for the home side, on 10 minutes, making no mistake with a powerful left-footed finish after a mis-kick out of the Fleet defence.
Nine minutes later, strike partner, Forbes made it 2-0 with a brilliant 20 yard strike, which gave Fleet keeper, Steve May no chance.
Eventually Fleet recovered their composure and began to play their fluent passing game. This almost bore fruit in the 35th minute when wingman Shaun Hale shot powerfully after a great passing move, and his shot was only inches over the bar, with the keeper beaten.
Fleet continued to press but conceded a third just before the break when Mancey netted from close range for his second of the evening.
Winchester continued to dominate after the break and sealed the match in the 60th minute when wingman, Danny Smith netted from close range, following a corner.
Fleet were denied a deserved consolation goal in the 80th minute, when Hale netted after a cross from Anstey. Having signalled the goal, referee Mr William Bull then reversed his decision after his Assistant insisted the ball hadn't crossed the line.
Fleet Town: May, Buckland, Millerick, (sub, Blakely, 65 minutes), Tiller, (Scammell, 72 mins), Jeffery, Saunders, Black, (Bax, 75 mins), Anstey, Smith, Leworthy, Hale. Subs (not used): Kendall, Sparshatt.