Boss went out with a game plan to ride Puissance De Lune quietly in the weight-for-age race then unleash him over the final 400m.
Puissance De Lune ($3.50 fav) was at the tail of the field on the home turn before he burst through a gap halfway up the straight and reeled in leader Ajeeb ($7.50) to score by three-quarters of a length. Last year's winner Second Effort ($7.50) was a long neck away third.
Boss, who labelled Puissance De Lune as the 2013 Melbourne Cup winner after last year's Queen Elizabeth Stakes, said the horse had the acceleration of a group one sprinter.
"This horse is that good he could win a Newmarket first-up," Boss said.
In winning the P B Lawrence first-up, however, Puissance De Lune will have to create his own slice of history if he is to win the Melbourne Cup.
No horse has won the Lawrence, formerly Liston Stakes, and gone on to win the Melbourne Cup that year.
Owner Gerry Ryan said the Cox Plate was also on the radar and he was thrilled with the win.
"Boss never drew the whip. He said he wasn't going to," Ryan said.
"All that talking up he's been doing, he might be right."
Weir was happy to get the first race of the spring out of the way and said the manner of the horse's victory was the most pleasing part.
- AAP