Sire de Grugy showed a return to winning form with a second victory in the Tingle Creek Chase at Sandown.
The former Champion Chase winner (10-3), trained by Gary Moore and ridden by his son Jamie, passed the post first.
However, there was a lengthy stewards inquiry after he clashed with runner-up Special Tiara as they jumped the final fence.
The pair battled it out to the line but Moore's mount hung on for victory and the stewards ruled in his favour.
Sire de Grugy, whose last win had come at Chepstow in February, had looked strong from way out after challenging Special Tiara, who set the early pace.
However, the 2013 victor jumped strongly left at the last fence and clashed with his rival in midair, leaving connections with some anxious moments before the result was confirmed to continue the trainer's recent good run of form.
"He always jumps left, he's jumped a bit left again at the last," said the winning jockey. "I thought Special Tiara was going to get by me, but he's toughed it out. He went again when Special Tiara got to me.
"This horse is my best mate."
Nina Carberry, who was bidding to become the first woman to win a Group 1 steeplechase in the United Kingdom, finished fourth on Somersby.
Earlier at Aintree, Highland Lodge (20-1) won the Becher Handicap Chase in the first race of the season over the Grand National fences at Aintree.
The Jimmy Moffat-trained horse, ridden by Henry Brooke, was victorious on his first start since being acquired by owners Bowes Lodge Stables last month.
"Jimmy Moffat did the hard work, and it was my job just to keep hold of his head," Brooke told Channel 4 Racing.
"I thought he had a good chance on that ground. I got to two out and thought: 'He's got some engine on him'."
Pineau De Re, the 2014 Grand National winner, and, at the age of 12, the oldest horse in the race, was an early faller at the second fence.
Analysis: BBC horse racing correspondent Cornelius Lysaght
The brave effort of Highland Lodge provided a major pot for the small Cumbrian training operation of Jimmy Moffat who rides the nine year-old himself most days.
Moffatt hopes to return to the big fences at Aintree "for the big one" in April though he might need a hike up the official ratings to get in.
An indication of the unpredictability of these obstacles came when Pineau de Re (12th and first in the last two Grand Nationals) fell at the second here.
Happily, like all the rest, he and his jockey were fine.