ROME (AP) Four-game sets.
A clock counting down between points.
And free crowd movement during matches.
A whole new set of tennis rules will be tested by the ATP Tour during a new season-ending tournament for the top 21-and-under players in Milan in November.
''This is one of the most exciting things we've done here at the ATP for a long time,'' Chris Kermode, the ATP executive chairman and president, said during a presentation of the Next Gen ATP Finals on Tuesday.
Sets will be first to four with tiebreaks at 3-3, and matches will be best-of-five sets with no-Ad scoring.
''We're trying to make more points relevant, more points of interest straight away - less down moments in the sport,'' Kermode said at the Italian Open.
Other rule changes include:
- Shorter warmups: Matches will begin precisely five minutes from the time the second player walks on to the court.
- Clock: A clock will be visible in between points to ensure strict enforcement of the 25-second rule, as well as during set breaks, medical timeouts, and the five-minute countdown during warmups.
- No lets: The no-let rule will apply to serves, bringing in an additional element of unpredictability.
- Medical timeouts: A limit of one medical timeout per player per match.
- Player coaching: Players and coaches will be allowed to communicate at certain points during matches.
In addition, the court will feature only singles lines - no doubles alleys.
But don't expect the new rules to be implemented on the rest of the ATP Tour anytime soon.
''We are not going to dramatically revolutionize the game in the next five years,'' Kermode said. ''Maybe some elements will come in but we're not looking to make change for change's sake. We are really test-casing things that fans have asked us to have a look at.''
By next week, top players Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic will each be 30 or over.
''We're probably coming to the end of one of the greatest eras of tennis that certainly I've ever seen, and what we need to do as a sport is look to the next generation of players and how we can put them on a platform, a showcase, to demonstrate to the world how great this next generation is going to be,'' Kermode said.
The top seven 21-and-under players of the season plus an Italian wild card will qualify for the round-robin tournament.
At No. 17, Alexander Zverev of Germany would be the highest-ranked qualifier for now.
Other potential qualifiers include No. 41 Borna Coric of Croatia, No. 54 Karen Khachanov of Russia, No. 65 Frances Tiafoe of the United States, and No. 66 Chung Hyeon of South Korea.
''We do have a strong group of guys who are playing great and who are getting up the rankings,'' Zverev said.
Zverev suggested that under-23 may have been a better cutoff, to allow players like Nick Kyrgios, Kyle Edmund, and Yoshihito Nishioka to qualify.
The rapidly rising Zverev also has a chance to qualify for the ATP Finals in London a week after the Next Gen tournament.
''That's something I look for more than Milan,'' Zverev said.
The Nov. 7-11 event at Milan's new Fiera convention center will award $1.275 million.
No rankings points will be awarded.
Andrew Dampf on Twitter: www.twitter.com/asdampf