She became the third player to record multiple victories this year, joining Jang Ha-Na and Lydia Ko. Nomura posted her first win on the US Tour in February when she captured the Women’s Australian Open crown.
Sunday’s Swinging Skirts competitors had to brave windy conditions which included gusts of up to 40 mph (60 km/ph) at the Lake Merced Golf Club.
But Nomura did a better job than most of handling the tricky conditions. She made three consecutive bogeys on the front nine to drop her lead to one.
But she recovered by draining a 70-footer for birdie at the par three, 12th hole to stretch her lead.
“I hit it right and it went 100 percent in,” said Nomura of the long putt.
The last Japanese player to post a pair of wins in an LPGA Tour season was Ai Miyazato in 2012.
Pace, who began the day tied for second, carded a 74 to finish at 283.