Neptune Collonges, an unfancied 33-1 shot, won a thrilling renewal of the John Smith's Grand National at Aintree on Saturday – but the race was marred by the death of the Gold Cup winner Synchronised who fell at Becher's Brook.

According To Pete was a second fatality at the same fence.

Heavily-backed 8-1 joint-favourite Seabass led over the final fence under Katie Walsh, but tired on the run to the Elbow and it was Sunnyhillboy (16-1) who took up the running under Richie McLernon.

Sunnyhillboy looked to have the race in the bag when two lengths clear with just 100 yards left to run, but Neptune Collonges, under a determined Daryl Jacob, gradually closed in and grabbed the verdict by a nose right on the winning post in one of the closest finishes in the history of the race.

Seabass held on for third, five lengths adrift, with Cappa Bleu (16-1) fourth for each-way backers.

For the second time in three years, Ruby Walsh had been forced to miss the ride in the National after an earlier fall in the Aintree Hurdle. Two years ago, a tumble from Celestial Halo forced him on to the sidelines and history repeated itself as favourite Zarkandar came down heavily at the sixth flight.

Walsh was able to walk back to the weighing room but was signed off by the doctor for the rest of the day. Paul Townend replaced him aboard On His Own, who fell when in contention at halfway.

Victory effectively sealed the jump trainers' championship for Nicholls, but it had looked only an hour earlier as if rival Nicky Henderson had stolen a march when Oscar Whisky (9-4) took advantage of Zarkandar's fall to complete a lucrative treble for the stable who had also landed the first two contests.

Oscar Whisky had previously finished well held in the World Hurdle at Cheltenham but appreciated the step back in trip and showed plenty of determination under Barry Geraghty to deny Thousand Stars by a neck – the same one-two as in the race 12 months earlier.

Sprinter Sacre (1-7 favourite) outclassed his three rivals in the Maghull Novices' Chase, coasting home by 13 lengths from Toubab.

"Anything but perfection is going to be disappointing from him," said Henderson.

"He's growing up all the time and he can only get stronger. He's getting very sensible, his scope and swagger is quite extraordinary. He has this aura about him.

"We've always said he knows he's very, very good looking, but just because they are beautiful it doesn't always make them the best, but with him it does - everything fits, he has the athleticism and attitude."

The treble for Henderson and Geraghty had begun with Simonsig (4-9 favourite), another to follow up a Cheltenham Festival success when taking the opening Mersey Novice Hurdle. In victory, he earned a quote of 3-1 from Paddy Power for next year's Arkle Chase.