Zenyatta worked six furlongs in 1:12.40 at Hollywood Park on Thursday, moving closer to an expected start in the $300,000 Clement Hirsch Stakes at Del Mar on Aug. 7.
Thursday's workout left jockey Mike Smith comparing her current condition to the way she felt in advance of her historic victory in the Breeders' Cup Classic at Santa Anita last fall.
"It was brilliant," Smith said. "It reminded me of her work before the Classic. She seems to be really back on."
Undefeated in 17 races and the champion older female of 2008 and 2009, Zenyatta has not started since winning the Grade 1 Vanity Handicap at Hollywood Park for the third consecutive year on June 13. Thursday's workout was her fourth since that race, preceded by a half-mile on June 27, five furlongs on July 5, and six furlongs on July 13.
Trainer John Shirreffs gave Zenyatta a few extra days between the July 13 workout and Thursday to align her schedule with the Hirsch, a race she won in 2008 and 2009.
Thursday, Zenyatta worked in company with stablemates Sarbonne and Green Cat, who was timed in 1:13. Sarbonne paced Zenyatta to the turn, when Green Cat became the pacemaker. Sarbonne was not given a workout time.
"As always, she was so professional," Shirreffs said. "She looked like her normal self."
Smith said Zenyatta's hard-fought half-length win over St Trinians in the Vanity tightened her up after easier wins in the Santa Margarita Handicap at Santa Anita in March and the Apple Blossom Invitational at Oaklawn Park in April.
"She probably needed a couple of races coming back," Smith said. "The other day was the first time she had to lay it down a little bit. I think it did her a world of good."
Zenyatta is owned by Jerry and Ann Moss.