Spain's Jaime Busto - Repsol Honda and Britain's Emma Bristow - Sherco will start tomorrow's opening day of TrialGP USA, round six of the 2017 FIM Trial World Championship and round one of the 2017 FIM Women's Trial World Championship, at the back of the field in their respective classes after topping qualification at Kingman in Arizona.

Busto took his third qualification victory of the season in the TrialGP class while Bristow opened up her account on top in TrialGP Women as the ladies' series got under way.

With sixty-six riders competing over three routes of varying severity on the steep, wooded hillside the action came thick and fast.

Although not the shortest it was certainly the quickest qualification section we have seen this year with the loose soil and imposing granite boulders providing a stiff test as riders threw caution to the win in a bid to post the fastest time without losing any costly marks.

After some impressive early results it was defending FIM Trial World Champion Toni Bou - Repsol Honda from Spain who looked to have his third consecutive qualification win in the bag with what seemed to be an unbeatable time of 0:33.25.

Then, with the large and enthusiastic American audience whooping their encouragement, Britain's James Dabill - Gas Gas did the unthinkable and posted a clean ride just over one second faster.

The stage was set for yet another Busto show - stopper and the nineteen-year-old, the penultimate rider to go, rose to the occasion to make it a hat-trick of qualification victories with a barnstorming ride over a second faster than Dabill that sent the crowd wild.

"I'm very happy with my performance today," says Busto. "I had to take some big risks because the section was very fast. The fans were very good and I enjoyed it, but now I must do the same again tomorrow."

Spain's Albert Cabestany - Sherco finally appears to have got to grips with qualification and was fourth ahead of compatriots Miquel Gelabert - Sherco and Adam Raga - TRRS.

Both female classes rode the same eased route and Bristow, who is going for her fourth consecutive TrialGP Women title, put in a Champion's performance that combined pace and precision.

The third rider in her class away, she was always in control and her clean ride in a benchmark time of 0:37.02 gave her victory by 0:00.78 over Spain's Berta Abellan - Beta with another Spaniard, Sandra Gomez - Gas Gas, third almost a further half-a-second adrift.

"The fans were great - really supportive - and it was a fantastic atmosphere, but I'm relieved to be honest," says Bristow. "It's the first time the women have had to do qualification and I think everyone was quite nervous."

"Obviously you want the clean which is the main priority, but you also want to go fast and I did both so I'll start at the back tomorrow which is important, but I've still got to produce the goods."

With fifteen riders staying clean in a close Trial2 contest on their own eased route it was Britain's Toby Martyn - Vertigo who defied team orders and hung it out for a time of 0:27.42.

Hakon Pedersen - Gas Gas from Norway and Spaniard Francesc Moret - Montesa were both within 0:01.14 of him in second and third as championship leader Iwan Roberts - Beta played it safe, ending the session eighth with a time of 0:32.00.

In the Trial2 Women class Spain's Neus Murcia - Beta stayed clean and posted a fastest time of 0:42.47 to qualify first over five seconds ahead of Jule Steinert - TRRS from Germany.

Some of the biggest cheers of the day were reserved for home heroine Maddie Hoover - Gas Gas who was a fighting third a further six seconds behind.

With qualification over, the American fans can now look forward to two days of pure Trial action that you can follow section by section by downloading the free TrialGP LIVE app on both the Apple store and Google Play today.