Everest favourite Nature Strip has thrown a scare into the Chris Waller camp after tossing jockey James McDonald and galloping riderless in a crucial barrier trial at Randwick.

Lining up in the only heat for older horses, the star sprinter reared as the gates opened, dislodging McDonald from the saddle.

McDonald was uninjured and rode in the remaining two-year-old trials while Nature Strip also appeared to come through the drama unscathed.

Waller's assistant trainer Charlie Duckworth said Nature Strip was standing placidly but uncharacteristically jumped in the air as the barriers opened.

"He seems to have pulled up absolutely fine," Duckworth told Sky Thoroughbred Central.

"I don't think he has taken any harm from it at all. It's just obviously what we do from here.

"But he is in one piece and James is in one piece. I don't think he did too much and he will benefit from the gallop, even if it was riderless."

Duckworth said the stable was yet to speak to stewards about whether Nature Strip would need to trial again before he lined up in the Premiere Stakes on Saturday week, his final race before The Everest on October 17.

The heat was won by the Anthony Cummings-trained Libertini but Monday's session was all about the latest crop of babies.

Several youngsters impressed across the nine two-year-olds heats but none more than the Ciaron Maher and David Eustace-trained Enthaar.

A daughter of Written Tycoon out of Not A Single Doubt mare Final Agreement, Enthaar was bred by owners Emirates Park and barely came off the bridle to win by almost five lengths.

Her time of 50 seconds flat was the quickest of the morning, the performance giving McDonald reason to smile after his dramatic start.

Maher said Enthaar was a natural racehorse and would press on to the Gimcrack Stakes at Randwick on October 3.

"She came up from Melbourne the other day and she just had a little 600 metre jump out, was very natural there and she has gone on," Maher said.

"We haven't had to do much with her and she looked quite good there again."

Tulloch Lodge filly Total Babe clocked the second fastest time of the morning and was one of three winners for Gai Waterhouse and Adrian Bott, along with Vaccine and Excela Bella.

Snowden Racing's Kalashnikov recorded the quickest heat time for the colts and geldings with an impressive five-length victory.