Webb, the former Southend manager whose headed goal took the FA Cup to Stamford Bridge in 1970, was welcomed 'home' with a three-month contract and told to show he was worthy of a long- term arrangement by the Chelsea chairman, Ken Bates, who, in characteristic style, announced his managerial change to surprised callers on the club's telephone information service.
Only 10 weeks ago Chelsea were fourth in the table and threatening to intrude on the title designs of Manchester United and Aston Villa. Yet Porterfield, 47 last week and himself an FA Cup winner for Sunderland in 1973, appeared incapable of arresting the decline which, in a catastrophic eight-day spell last month, saw them removed from both the Coca-Cola Cup and the FA Cup.
Yet again, long before the season's end, Bates had to swallow the unpalatable truth that the silverware was destined for somebody else's sideboard, and that could only spell trouble for Porterfield. Successful in securing the club's future at their London home, Bates could afford to spend more time on team matters and, never one to fiddle around while hopes burned, he decided Saturday's defeat by Aston Villa, the 12th game they had failed to win in a miserable sequence was one too far.
'We have reviewed the results and the fact is we lost as many as we have won over the last two seasons,' Bates said. 'That's not in keeping with our aspirations.'
Unaware of developments, Porterfield took the usual training session yesterday morning before learning he would be the first Premier League manager to lose his job. 'We have parted on amicable terms and wished each other all the best,' Bates added.
'We were looking at the situation all the time and I decided over the weekend that it was time to make a change. We have been plagued with injuries and we have not had the rub of the green. By making changes at this time it gives us a chance to get things straight for next season. David Webb was very successful at Southend and is Chelsea through and through.'
It was Porterfield's second spell at the club, he enjoyed a successful partnership with Bobby Campbell before moving to Reading in November 1989 for his fourth spell in management, having already served at Rotherham, Sheffield United and Aberdeen.
He was sacked by Reading 17 months later and returned to Chelsea in June 1991. He spent pounds 6m in a glory quest which was rich in potential but thin on substance. Last season's FA Cup quarter-final defeat by Sunderland typified their ability to foul up on the big occasion.
After 230 League appearances for the Blues, Webb moved on to Queen's Park Rangers, Leicester and Derby. As a manager he guided Bournemouth to promotion from the Fourth Division and, after a spell with Torquay, led Southend to successive promotions before falling out with the chairman, Vic Jobson, last season.
Of his new challenge, Webb said: 'Chelsea and their supporters haven't had a great deal to cheer about in the last 20 years and it is up to me to do my best and give them back some success.
'Ian Porterfield is a good friend of mine and I'm sorry to see him go in such circumstances, but the door to success is the same distance away as the door to failure.'
Porterfield was joined in the search for a new job by Alan Murray, who was dismissed by Hartlepool, of the Second Division, just six weeks after he led them to a memorable FA Cup victory over Crystal Palace. Earlier this season, his side stood second in the table, their highest position in 72 years, but since the Palace defeat on 2 January they have gone nine games without so much as a goal.
Viv Busby, out of work since he was sacked as Sunderland coach 14 months ago, takes up his first managerial appointment as Murray's replacement.