An eight-year-old with a history of tendon trouble added to Chris Waller's unstoppable run in Sydney racing at Randwick on Thursday.

I'm Imposing, an imported stayer who found his way into Waller's premiership-winning stable after starting his Australian career as a member of Lloyd Williams's string, was precise in his final stride to deny topweight Travolta in the Group Three Summer Cup (2000m).

The pair had the $125,000 race to themselves for most of the straight with I'm Imposing poised for a clear-cut win until Travolta lifted strongly enough to momentarily regain the lead metres before the finishing post.

But just as Travolta ($6.50) was about to be acclaimed for an off-the-canvas triumph, I'm Imposing made a final lunge and it was enough for the gelding to score by a half head.

The favourite Destiny's Kiss ($3.80) raced a long way out of his ground before running on late to finish three-quarters of a length away third.

I'm Imposing's win, his fourth in a career restricted to 21 starts, wasn't a total surprise because he firmed from $20 to $14.

And Waller's foreman Peter Muscott said the betting move reflected some stable confidence surrounding the horse who went amiss not long after joining the yard 18 months ago.

Muscott saw more merit than I'm Imposing was given credit for in his first-up run but the clincher, to his eye, was the horse's Randwick barrier trial on December 16.

"The trial was very, very good. I was quietly confident today," Muscott said.

With leading jockeys Nash Rawiller and Hugh Bowman suspended, Blake Shinn made the most of his call-up to ride for Waller.

"It was a great training effort," Shinn said.

"Full credit to Chris Waller.

"I really thought I was going to win by a couple of lengths at the two hundred metres but the second horse put up a great challenge."

Waller's first Summer Cup win completed a Boxing Day treble for the trainer but he missed the feature meeting to spend Christmas in New Zealand with his family.

Earlier he kept Made To Order on an ATC Oaks trail with her win while Acapela claimed her second race since coming from New Zealand.