Shot clocks and reduced warm-ups appear very likely to be introduced to the ATP Tour - and possibly next season.
A number of innovations were trialled at the inaugural Next Gen ATP Finals in Milan last November.
First to four game sets, no advantage scoring or service lets and coaching via headsets were among the trials.
But it is a 25-second serving clock and a reduced warm-up which players can expect to face on tour in either 2019 or 2020.
The shot clock is set to be enforced at a Grand Slam for the first time during this year's US Open.