STANFORD, Calif. — It did not seem especially noteworthy when Angelique Kerber summoned her coach, Torben Beltz, after the first set of her opening match at the Bank of the West Classic here last week. Under WTA rules since 2008, players can call for 90-second on-court coaching visits once per set.
But there was a twist. Beltz was able to fortify his burst of advice with nearly real-time data delivered from a WTA-issued iPad he had been monitoring in his seat.
Beltz told Kerber that her opponent, Daria Gavrilova, was serving to her backhand nearly every time.