WIMBLEDON, England — The signature checkerboard headband was back on court at Wimbledon on Wednesday, wrapped snugly around the dynamic mind of Pat Cash on the 30th anniversary of the day he scored his first and only major title.

But Cash was not serving to Ivan Lendl on this day, as he did so brilliantly on July 5, 1987. Instead, he was pounding balls over the net to CoCo Vandeweghe, his newest pupil, whom he hopes to take to the top of the women’s game.

Vandeweghe is a talented 25-year-old American, ranked 25th in the world. She reached the semifinals at this year’s Australian Open and the quarterfinals at Wimbledon two years ago. But other than that, her results have not matched her potential, at least in Cash’s eyes.

“I don’t understand why she is No. 25 in the world,” Cash said after running her through a workout on the No. 1 practice court. “She should be No. 5 in the world. I know she’s had some injuries and that doesn’t help.”