LOVE him or loathe him – and the overwhelming majority of those who held an opinion were in the latter category – it seemed you just could not keep a bad boy down.

El-Hadji Diouf, described by one critic as a walking ASBO (anti-social behaviour order), came with so much baggage even his biggest fan was not sure whether he was worth the trouble.

Sam Allardyce, the man with the reputation for saving lost souls, knew he was taking on his biggest ever challenge when he signed him on loan from Liverpool at the start of what became a momentous season for Bolton Wanderers. But he could not have envisaged the impact the Senegal striker would have on his club’s fortunes.

Talk about having to take the rough with the smooth. That did not come close to describing the dilemma Allardyce was wrestling with as he considered whether to ask his paymasters to inject hard cash into making his transfer a permanent one.

On the one hand Diouf was a spitting, diving, night-clubbing embarrassment. On the other a likeable rogue most Bolton fans saw as a gifted footballer, an entertainer, a matchwinner who just happened to have flaws in his character neither he nor anyone else seemed capable of controlling.

At his worst he was a liability, at his best he had the ability to return from a three-match ban for a rash tackle on Jens Lehmann which left his team-mates to fight a losing battle in their FA Cup quarter-final against Arsenal, to single-handedly turn this crucial game on its head.

Ten minutes into the second half, Wanderers were in danger of losing a game they had led against a Charlton side there for the taking.

Allardyce, fearing the initiative was swinging decisively in the home side’s favour, decided to send on the errant El-Hadji in place of Kevin Davies.

And within four minutes he was skilfully finishing the move of the match to secure a victory that put Wanderers on the threshold of a Champions League dream.

His performance was brilliant, his behaviour impeccable and his reputation . . . unfortunately that was something he had to live with.

It was amazing what a difference one player could make. This was the fourth time in 13 games 24-year-old Diouf had personally tipped the balance and the temptation on those statistics alone was for Wanderers to stump up the cash to convince Liverpool to let them keep him at the Reebok beyond his loan.

But Allardyce, although delighted with his contribution in such a pivotal game, spelled out his reservations.

Diouf had missed six games through suspension and Big Sam was quick to remind him of the cost of his latest indiscretion as he weighed the pros and cons.

“He needed to pay us back for missing the last three games and for costing us a place in the FA Cup semi-final,” the manager said, “and these are the things the owners have got to consider when they decide what to do in the summer.”

It certainly looked as though Wanderers would be planning for their first season of European football. The only question was which competition?

Alan Curbishley’s Addicks would have been in with a shout of a UEFA Cup spot had they won the game.

As it happened they dropped to 10th in the table, well out of contention while Wanderers went up to fifth, leapfrogging Liverpool, who were held to a 2-2 draw by Spurs.

The top four were Chelsea, Arsenal, Manchester United and Everton and Allardyce made no bones about what he was aiming for.

Rapping out a catch-us-if-you-can warning to the chasing pack of Middlesbrough, Aston Villa and Spurs, the Bolton boss insisted he was not going to settle for the UEFA Cup.

“The Champions League is a long shot for us because we’ve got to rely on Everton slipping up,” he said, careful not to put too much pressure on his players as the prospect of a last-match showdown with the Mersey Blues became ever more likely with every passing game.

“We would dearly love to continue the way we are going because we all know what’s round the corner.

“Everton is our last game at the Reebok and when that comes round we’d dearly love to have something hanging on it.

“Can we catch them? Can we get close to them and pip them? That would be a great end to the season, but this will have been a great season no matter what.”

The season was certainly building up to an exciting climax with victory at The Valley making it nine wins and two draws in a 13-match run that had propelled Wanderers into the Euro mix.

Allardyce appeared to be taking a gamble when he substituted Diouf for Davies 10 minutes after half time.

Jay Jay Okocha had given Wanderers the lead from the penalty spot in the seventh minute after Herman Hreidarsson had handled in the box under pressure from Davies. But when Francis Jeffers fluked an equaliser on 29 minutes – his shot took a double deflection off Stelios and Fernando Hierro – the match was back in the balance and the longer it went on, the more concerned Allardyce became.

What he could not have known when he made the substitution was that it would pay such instant dividends.

Nicky Hunt started the move deep in defence and Okocha took it on before Diouf fashioned the opening with a terrific ball down the line to Stelios. His cross was headed down by Gary Speed for Diouf, who had continued his run, to cushion a header over Kiely.

Wanderers’ critics had castigated their playing style as route one, one-dimensional and long ball. Goals like this were the perfect riposte.