Gemirande defended strongly against the favorite Madara and won the Gold Cup at Cheltenham in December.
The pair moved away from the rest of the field on the approach to the penultimate place and met briefly during her jump.
Until the last moment before the shot at 11-2 they were still together, led by Charlie Deutsch and trained by Venetia Williams, they overtook the favorite 11-4 and kept the advantage to win by a hair.
Madara, ridden by Harry Skelton and trained by brother Dan, was much better than third-placed Fugitif (6-1), who won last year’s race.
Gemirande, an impressive winner last time at Ascot, was in a strong position throughout and Deutsch was delighted to give the eight-year-old another big race win.
“His jumps were electrifying and I’m delighted that he took the lead. He loves racing,” he told ITV Racing.
“He’s a real character – the more you pull, the faster he goes, but he can really play.
“Venetia is a magician in what she does with her horses.”
