Jockey Dwayne Dunn had more trouble getting Our Nkwazi to the starting gates than he did pushing the gelding to a surprise win at Moonee Valley.

Dunn and Our Nkwazi's handlers spent five minutes cajoling the eight-year-old to canter to the barriers but the sprinter took less than 60 seconds to claim the United Refrigeration Handicap (1000m).

"He's got a few little tricks we need to deal with," Dunn said.

Few punters thought the Shawn Mathrick-trained Our Nkwazi could upset the favourite Lord Of The Sky, who was dropping back in class after disappointing in last Saturday's Group Three Bletchingly Stakes at Caulfield.

An irregular midweek blood count forced trainer Robbie Laing to treat Lord Of The Sky with antibiotics, which prompted punters to let the four-year-old drift from $1.50 to $1.90 while Our Nkwazi eased from $26 to $31.

Lord Of The Sky began fairly but mustered his usual pace to share the lead with the Darren Weir-trained mare Siwa Lady with the pair covering the first 600m in a quick 34.65 seconds.

The hectic pace proved too much for Siwa Lady approaching the home turn while Lord Of The Sky lasted until the 200m before he punctured.

"He jumped clean enough and had a good enough run to think he should have finished off a bit better than that," Lord Of The Sky's jockey Kayla Nisbet said.

"By the time we straightened up he was at his top and he weakened from there.

Neither Laing nor Nisbet would blame Lord Of The Sky's treatment for the favourite's failure while a vet's exam revealed no issue with the sprinter.

Dunn brought Our Nkwazi with a late run to beat Solsay by a half-head, denying those that backed the runner-up from $5 into $3.90.

Our Nkwazi's win was especially sweet for Dunn, who received criticism from some sectors for his Bletchingly Stakes ride on Lord Of The Sky.

"A few potted me last week," Dunn said.

"It's always a big pleasure to come back and ride a winner."