"It is good to get that out of the way. The pressure is off now," Butcher said.
He won with Mister Dann four races later.
The 21-year-old, employed at the Clevedon stable of Barry Purdon, is in his fourth season as a junior.
His previous best tally was 59 wins last season.
He has driven 222 winners since his first on Clonmel at Alexandra Park in August 2008.
He began working with his father, David, at Cambridge and he is in his second season with the Purdon stable.
"Barry [Purdon] has been very good to me with drives," Butcher said.
"It was a big thrill to get my first group one win for him with Cheer The Lady in the New Zealand Oaks. It is also great to win a race for my family connections."
He has driven Claudia Cardinal, trained by his father and grandfather (John) and raced by members of the Butcher family in two wins.
Zac had driven El Magic to win a heat of the series at Forbury Park a week earlier.
El Magic and Mister Dann are trained by Peter Scaife of Foxton, who is campaigning a team at Forbury Park from his Waikouaiti base.
Scaife has won 38 races this season, surpassing his best tally of 37 achieved in 2009-10.
Miss Pegasus cleared maiden trotting ranks by a winning margin of 12 and three-quarter lengths last night.
Miss Pegasus was having her 10th start. She had been minor-placed six times.
Trained by Phil Williamson for breeder Woodlands Stud, of Auckland, Miss Pegasus is by Pegasus Spur and the seventh foal of Merinai, who won 19 of her 27 starts.
Merinai won her first nine races and subsequently eight in a row including the Dominion Handicap and the Rowe Cup in the 1997-98 season.
