After battering the gallant though outclassed Brian Nielsen to defeat, Mike Tyson said he needed two more fights before he would be ready to attempt to regain the world heavyweight title. He is probably right, but the television powerbrokers who dictate the course of the old champion's career may be unwilling to wait.

"The clock is ticking for Mike. He's 35 now and he does not have forever," the head of Showtime television, Jay Larkin, said after watching Tyson go through a far harder test than expected, with Nielsen retiring on his stool at the end of the sixth round after a display of bravery which will only add to his folk-hero status in Denmark.

Derided as the "Danish pastry" by a sceptical American media, the well-padded Nielsen had arrived in the ring to the strains of Always Look on the Bright Side of Life from Monty Python's Life of Brian and there were plenty who suggested he would be nailed to the canvas before the end of the first round.

But he absorbed huge punishment, eventually pushing Tyson far enough into the fight to give him the competitive rounds he needs so badly if he is going to be able to hone what remains of his athleticism and boxing skills to provide a credible argument that he is capable of beating the winner of the Hasim Rahman-Lennox Lewis rematch on Saturday, November 17th.

"If Lennox wins that fight there is a real possibility that we can reach agreement with HBO the American TV company to which Lewis is contracted for a Lewis-Tyson fight to be staged in March or April next year. Rahman might be more difficult," Larkin said.

Although he did not say as much, Larkin knows a Rahman victory would necessitate dealing with Don King, who would like nothing better than the role of ransom demander in chief, especially since Tyson, his former charge, has a lawsuit pending in which he claims King defrauded him of $100 million in ring earnings.

Possibly Tyson will be allowed another warm-up fight in January in the US to whet the appetite of the lucrative American pay-per-view market. Larkin said: "Maybe, and we will talk about it, but we will have to take the greatest care in selecting the opponent."

Any slip-up of the Lewis variety, when he was poleaxed by the unfancied Rahman, and the one remaining mega-fight of Tyson's generation could be lost for ever.

Hard though Nielsen tried, an upset rarely seemed likely in front of the 20,000 crowd gathered in the Parken stadium, except when Tyson's stamina looked in danger of running out in the fourth and fifth rounds. The old champion plodded wearily back to his trainer Tommy Brooks, who deserves much credit for instilling a sense of self-discipline in Tyson which had been absent in recent contests.

For the first three minutes Tyson rolled back the years, unleashing a blistering onslaught. A clash of heads opened a cut on Nielsen's left eyelid in the second, and two left hooks in the third sent the 181/2st Dane to the floor for only the second time in his career.

But when Tyson fired a low blow to leave Nielsen on the canvas in agony as the bell rang, there were worries he would once more press the self-destruct button. The fact he maintained his composure while referee Steve Smoger gave Nielsen time to recover perhaps shows that, at long last, he realises there can be no more disgrace.

The end came after the sixth round, with Nielsen's left eye swelling alarmingly and the Dane telling the referee his vision was affected and agreeing he could not go on.

It left Tyson frustrated by his inability to find a knockout but saying: "I'm back. He's a tough guy who was hard to hit. He's big and I weighed more (the heaviest ever at 17st 1lb) because I wanted to put more leverage into my punches. He fought a great fight."

Upon quiet reflection, Tyson may be worried about the way he appeared to run out of steam as he looked for a knockout punch with lunges of increasing desperation. As his manager Shelly Finkel agreed yesterday: "Nobody is a harsher critic of Mike than Mike himself."

Joe Calzaghe, meanwhile, is being lined up for a US debut appearance in the new year after crushing American Will McIntyre in the fourth round in Copenhagen to successfully defend his WBO super-middleweight title for the ninth time.

McIntyre was outclassed, and Calzaghe, who remains undefeated in 32 fights, may be steered towards Canada's Eric Lucas, who holds the WBC version of the title, or David Reid, who was the only US gold medal winner when he won the light-middleweight title in the 1996 Atlanta Olympics.

"I don't mind who it is. Bring on Roy Jones, Bernard Hopkins, anybody. I don't fear them and I am ready for the world. I know I am the best fighter Britain has and I should be ranked alongside the best champions," said Calzaghe.

"Beating McIntyre has given me great exposure across the world. Britain and Europe knows me, and America is finding out. I cannot wait to go there and fight."