The unstoppable Chris Waller was back in the Group One winner's stall at Randwick on Saturday after Boban produced a spectacular finish to deliver him his first Epsom Handicap.

The four-year-old overcame a bad check near the 600m to regain his composure and storm down the outside of the field, snatching victory from bonny mare Streama in the final bound.

Glyn Schofield went from thinking Boban was a forlorn chance midrace to believing the horse was going to win comfortably halfway up the straight, only to hit the line unsure whether he had arrived in time.

"When they steadied up midrace and he got onto the bit and Jimmy (Cassidy on Riva de Lago) whipped up around me, it fired me up a bit," Schofield said.

"At that stage I had to come right off heels but fortunately I got onto Riva De Lago's back who gave me a beautiful suck run up the rise.

"I peeled off his back and I thought we were just going to win by a length but the long run he's made, of course he couldn't sustain that right the way through.

"I'm just happy my number has gone up. From thinking I was going to win by a length to winning by a pimple, I'm happy with the pimple."

Boban has shown promise throughout his career, which began with Anthony Freedman before he was transferred to Waller at the start of the year.

He hasn't been able to put it all together until this spring and Waller puts that down to maturity.

The Epsom triumph was Waller's third Group One this season following Zoustar's Golden Rose victory and Foreteller's Makybe Diva Stakes win in Melbourne.

Guy Walter had to settle for the minor placings with his pair Streama and Toydini but was gracious in defeat, paying tribute to Waller's remarkable strike rate.

"He's a hard man to beat," Walter said.

"But there's always another day."

While Schofield wasn't sure if Boban had arrived in time, Hugh Bowman aboard Streama thought she had won.

The pair hit the line wide apart and Bowman felt that contributed to her downfall.

"She actually fought off the other one (Toydini) and she couldn't see Boban," Bowman said.

"Had she been able to see him I think she would have fought him off as well."

Boban ($6) scored by a nose over the favourite Streama ($4.60) with Toydini ($6) another long head away.