The 44 year old German-born US rider who is based in San Diego, California, clinched victory with a score of 77.915%, pinning nine-time World Cup champion Anky Van Grunsven into second spot while German star and two-time World Cup winner Isabell Werth had to settle for third place.
Steffen Peters and Ravel (USA), winners of the Grand Prix first round of the World Cup final.
Ashley Holzer of Canada went into the lead with Pop Art just before the half-way break, but The Netherlands' Hans Peter Minderhoud pushed them down the order with a better mark for Exquis Nadine before Werth and Satchmo changed the leaderboard once again when fourth-last of the 14 starters to take their turn. Werth's score of 73.745% was immediately surpassed by a mark of 74.170% from the defending champion whose horse, IPS Painted Black, produced some spectacular extended trot.
It was Peters however who completely stole the show with a magical performance from his 11 year old bay gelding. Just as they had done in the practice session the previous day, the pair remained totally in tune with one another, Ravel earning nine out of 10 marks from one judge for his excellent piaffe and two nine-point marks for a fabulous extended canter while Peters himself was awarded nine points for his riding position. Fans at the ringside waved a huge flag reading "Bring it home Steffen" and he did just that, the final partnership of Monica Theodorescu and Whisper finishing seventh when scoring 70.170%.
Van Grunsven could not bring her triple World Cup winning ride Keltec Salinero this time around and was further hampered during the qualification period by a recurring back injury which kept her periodically out of the saddle but she was pleased with her horse's effort. "Riding him here has been a new challenge for me, I was not sure how it would be but his confidence is growing and I'm satisfied and feel very happy with my second place today" she said.
Werth said she had to be cautious when going into her first pirouette because Satchmo was nervous of the sound of camera-shutters - "please don't click on Saturday night!" she said with a laugh to the photographers.
Ravel however was totally at ease in the electric atmosphere and Peters found it hard to describe his delight at the final result. "He gave it all to me today, I didn't have to push him hard he just gave me all the movements - I'm beside myself with excitement!" he said.
"He was just like this yesterday in the warm-up, even when the spectators were clapping and screaming when he was executing some of his movements. He is showing so much more maturity since he competed at the Olympics in Hong Kong which was his first big international event. Today we didn't have to hold back and I could take some calculated risks and they really paid off. I can't tell you how happy I am!" he declared.
The Grand Prix result however does not influence the battle for the 2009 Rolex FEI World Cup dressage title which will be decided on Saturday night during the Freestyle competition, and a huge influx of Californian supporters are expected to turn up to watch the battle played out under the Las Vegas spotlights.
Friday's schedule at the Thomas & Mack Center promises plenty more entertainment with world-class competition in the Olympic/Grand Prix Pas de Deux Challenge which will feature big stars performing in pairs. This will be followed by the International Superstar Young Horse Exhibition but the highlight will be the emotional retirement of Debbie McDonald's mare Brentina, the only US dressage hose to win the World Cup final. The partnership represented the USA at both the 2004 and 2008 Olympic Games and led the team to bronze medal position in Athens in 1999.
"It was six years ago that Brentina and Debbie McDonald earned the United States' first and only FEI World Cup Final Championship, so it is only appropriate that they return here to Las Vegas to celebrate a career that is one of the all-time best in the sport of dressage," said Pat Christenson, President of Las Vegas Events.