Hughes' day had had the most unpromising of beginnings. Left out of the starting line-up, he sat on the bench in growing frustration as Liverpool, playing typically silky football, scored twice in the first 21 minutes and held the lead until half-time.
Then Hughes was unleashed. The atmosphere was already simmering - adding Hughes was like putting a lighted match into a powderkeg. Chelsea exploded with three goals in 13 minutes, the first scored by Hughes, the second made by him. The third came from Gianluca Vialli whose selection ahead of Hughes had, at half-time, seemed mistaken. With 15 minutes left Vialli added a fourth and Chelsea were through to a fifth-round tie at Leicester City.
In the acres of football that now cover the television landscape there occasionally comes a match which justifies all the pre-kick-off hype. This was one of those matches. It had everything bar a penalty and a sending off - and there could have been a few of those had referee Steve Dunn not kept calm amid the maelstrom.
There was bewitching skill from nimble feet and quick minds, passion and strength, good tackles, great saves, stunning goals and, inevitably, a few errors. The work-rate was astounding. Players like Steve McManaman and Robbie Fowler were regularly seen helping out in defence. It was an intoxicating mix of the best of the British game and the sheen of the Continental, and it was not only the foreigners who were skilful or the British who worked hard. You could not take your eyes off it. The Spice Girls could have streaked across the deserted Shed End unnoticed.
When the dust settled, a teeming Stamford Bridge emptied and the television nation switched on the kettle, Liverpool were left to contemplate 17 days which had seen them tumble out of two cup competitions. Now, more than ever, they must maintain the League challenge.
Chelsea, meanwhile, have served notice that they have resilience to go with their skill. The team spirit, while not on a par with Wimbledon, is a far richer brew than usually associated with the club. Yet Leicester will approach the fifth round with hope. Chelsea are not yet as formidable on the road as at the Bridge.
One weakness, the absence of Michael Duberry, was quickly exposed yesterday. Jason Mc- Ateer's cross from the right seemed innocuous but Frank Sinclair missed his jump, the ball came to Stig Inge Bjornebye whose cross-shot was touched in by Robbie Fowler.
Eleven minutes later Gianfranco Zola played a bad square pass to Eddie Newton, his touch betrayed him and released Stan Collymore. Nil-two and, apparently, all over. Liverpool had not lost from a two-goal lead for 33 years.
Chelsea needed a goal and, after half an hour, Vialli should have provided it but shot over. A minute later Fowler should have sealed the game for Liverpool but headed past. McManaman also wasted a good chance but it seemed not to matter.
Enter the Welsh dragon, breathing fire. Liverpool, regular victims during his career, were unnerved. Four minutes later he held the ball up then turned in characteristic fashion to shoot low into the net. Liverpool now looked as if they had encountered a snarling dog and Chelsea, smelling their fear, went for the jugular.
Roberto di Matteo, pushed forward to harry John Barnes, had one shot saved then another blocked. Hughes was able to toe that to Zola who bent a rocket of a shot past David James.
The game see-sawed, Fowler and Zola both missing chances, before Vialli came in from the cold. As Zola found Dan Petrescu he glided in from the wing. The Romanian spotted his run, the pass and execution were perfect.
James made three excellent saves from Di Matteo and Villia but Chelsea's Azzurri would not be denied. Vialli won a free-kick on the right, Zola floated it in and Vialli, unchallenged, headed past James.
Chelsea's celebrations mirrored Newcastle's after the 5-0 eclipse of Manchester United. Newcastle did not win again for weeks; fortunately Chelsea have a few weeks to recover before the next round.
Goals: Fowler (10) 0-1; Collymore (21) 0-2; Hughes (49) 1-2; Zola (58) 2-2; Vialli (62) 3-2; Vialli (75) 4-2.
Chelsea (3-5-2): Hitchcock; Sinclair, Leboeuf, Clarke; Petrescu, Wise, Newton, Di Matteo, Minto (M Hughes, h-t); Zola, Vialli. Substitutes not used: P Hughes, Grodas (gk).
Liverpool (3-5-2): James; Kvarme, Wright, Matteo; McAteer, Redknapp, Barnes, McManaman, Bjornebye (Berger, 73); Collymore, Fowler. Substitutes not used: Carragher, Warner (gk).
Referee: S Dunn (Bristol).
Bookings: Chelsea: Sinclair, Wise. Liverpool: Fowler, Collymore.
Man of the match: M Hughes.