The team in white celebrated wildly. Reduced to 10 men in their semi-final second leg on 24 April at the Camp Nou, they'd held on for an improbable 3-2 aggregate victory over Barcelona to reach the European Cup final.

Earlier in the season they'd looked in disarray. An upstart young manager who was supposed to oversee the rejuvenation of the squad had been ousted after alienating a core of senior players, but a safe pair of hands everybody assumed was a short-term appointment had arrived, soothed egos and reawakened some of the old fire.

The league was beyond them, but doggedly they'd scrapped their way through to within one game of the prize – the greatest prize – that had eluded them through all their years of success. In that final that side in white faced Bayern Munich. Undone by some scandalous refereeing, they lost and were never the same again.

The similarities with Leeds United in 1974-75 and Chelsea's success at the Camp Nou 29 years later are striking. Of course the Barcelona then, despite the presence of Rinus Michels in the dug-out and Johan Cruyff and Johan Neeskens on the pitch, did not have quite the aura of the present-day side. And Leeds, having won 2-1 in the first leg, scored their away goal early, Peter Lorimer latching on to a Joe Jordan knockdown after eight minutes.

But then too, Barcelona were disappointing. "They did not spread their attacks wide enough to worry their opponent," wrote David Lacey in the Guardian. "It was a strangely muted performance from a team who many people had thought would sweep all before them in Europe this season." But almost as soon Barcelona had levelled on the night through Manuel Clares after 69 minutes, Gordon McQueen was sent off. "McQueen played Clares with such vitality," Lacey wrote, "that it was nearly a minute before the Barcelona player could be brought round, and he played to the end mopping his wounded head with a pad … it is a pity that on the threshold of their greatest triumph they should now be faced with problems caused by one of those irritating losses of control which have so often marred the club's success."

The correspondences between two semi-finals played on the same date 29 years apart are coincidence, of course, but what is significant is the underlying similarity between their side now and Leeds then. André Villas-Boas is not as abrasive as Brian Clough, and almost certainly didn't gather the Chelsea players together on the training field, as Clough did at Leeds, and tell them to throw their medals in the bin because they'd won them by cheating. Yet there were training-ground spats and the sort of confrontational team meetings that characterised Clough's time at Leeds.

Nor did Villas-Boas follow a hugely popular manager who'd formed the club in his own image over a period of 13 years; Carlos Ancelotti was popular but had been there only two years and this, anyway, is a side moulded by José Mourinho. But the intrinsic issue, of a core of players who had grown old together and who saw themselves as the heart of the club resisting change and the agents of change. Jimmy Armfield, the Roberto Di Matteo of the piece, said he had the hardest job of any Leeds manager because he was the one who had to tell Billy Bremner, Norman Hunter and John Giles that they were finished. The left-winger Eddie Gray – injured so often, Clough said, that if he'd been a racehorse he'd have been shot – even suggested one of the reasons Revie had decided to leave Leeds and take the England job was that he couldn't bear to break up the side he had built.

Leeds came ninth in the league that season, and spent the rest of the decade puttering about mid-table, never finishing higher than fifth before being relegated in 1982. Armfield left in 1978, and was replaced by Jimmy Adamson, who resigned two years later. After that, their came the first of the former Revie players, Allan Clarke, who oversaw the relegation. He was followed by Eddie Gray and then Billy Bremner, neither of whom could bring promotion – a warning, perhaps, should Roman Abramovich be tempted to turn to John Terry.

Assuming Abramovich's interest remains keen, of course, there is little chance of Chelsea being relegated, not even in seven years' time. Modern football has a series of checks in place to prevent the big clubs ever falling too far. But those seasons of stagnation – albeit probably bobbing around challenging for fourth rather than mid-table – are a genuine possibility.

Villas-Boas was appointed for a reason which was to manage the transition to a younger squad with a more dynamic style of play. That still has to happen: superbly as Chelsea played against Barcelona – and at times in the second leg against Napoli – the odd stint of dogged resistance from ageing limbs is not going to bring a league title. Whether Villas-Boas tried to change things too quickly, whether his approach would ever have worked, whether he was over-confrontational or whether that was inevitable in the face of his squad's conservatism, is debatable, but what is not open to dispute is that change was necessary.

It still is – and whatever happens in Munich next month doesn't change that. The example of Leeds three decades ago shows that a team in decline can still reach a European Cup final; Chelsea cannot let that disguise the underlying trend.