The other runners included the outstanding Irish mare Like-A-Butterfly. Trabolgan tracked Comply or Die for most of the race and recovered from a bad mistake at the second last fence to take the lead approaching the last. In the closing stages Trabolgan drew clear to win by three lengths from Comply or Die with Cornish Rebel a further three lengths back in third. Trabolgan began his 2005/2006 campaign on 26 November in the Hennessy Gold Cup, a handicap race over three and a quarter miles at Newbury, in which he was matched against more experienced chasers. He was assigned top weight of 166 pounds (11 stone 12 pounds) and started at odds of 13/2 in a field of nineteen runners. Mick Fitzgerald, who was returning from a long absence after suffering a serious neck injury, positioned the gelding just behind the leaders and maintained his position despite two bad jumping mistakes before moving up to challenge for the lead four fences from the finish. Trabolgan took the lead at the second last fence, held off the challenge of L'Ami, and pulled clear in the closing stages to win by two and a half lengths. The horse had carried the highest weight to victory since Burrough Hill Lad more than twenty years previously: the only other horses to have carried a higher weight had been Arkle and Mill House in the 1960s. Henderson, who was winning the race for the first time said: "It's taken me 25 years to do it. Mick struggled to get back and to do that is special for everybody". Following his victory at Newbury, Trabolgan was regarded as a leading contender for the 2006 Cheltenham Gold Cup and was expected to reappear in the King George VI Chase at Kempton on Boxing Day. Shortly after his win, however, the gelding became lame and scans revealed a tendon injury. It was hoped that he would return in time for the Gold Cup but the injury proved more serious and he was ruled out for the rest of the season. At the time, Henderson described the decision to rest the horse as "precautionary more than anything and luckily he is a young horse with half his career still ahead of him". Repeated injury problem meant that Trabolgan did not race again for more than three years. He returned as a ten-year-old, with Henderson expressing cautious optimism, but suffered from breathing problems and was unable to recover his old form. In December 2008 when he was pulled up two fences from the finish when tailed off in a handicap at Ascot.