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.

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The shot clock is set to be enforced at a Grand Slam for the first time during this year’s US Open.

It was used in Australian Open qualifying and will also be in operation during French Open qualifying this month.

Wimbledon, which has opted not to use it this year, says it will adopt a “wait and see” approach.

Some leading players have voiced their concerns at the shot clock, with 16-time Grand Slam champion Rafael Nadal particularly unhappy.

ATP executive chairman Chris Kermode, speaking at the launch of this year’s Next Gen Finals, said he thinks the proposed changes will happen.

“I think that’s a good thing,” he said.

“When we first started this we never committed to what date we would do any of these, because we needed to take a cautious approach.

“I think we can also look at the medical time outs and the toilet breaks, again to speed up play. I think we can get those done quite quickly as well.

“When it comes to the scoring of the game, that’s getting into the ethos of the sport and that takes much longer because you do need everyone to buy into this.

“I personally loved it: what was incredible was the intensity from point one. But I’m doing this as a collective; I’m not running it as a dictatorship. So all the traditionalists don’t need to panic that I am single-handedly going to do this. I personally like it, but we’ve a long long way to go until we do anything else.”

The format for the second Next Gen Finals will be almost identical to the first, although the warm-up will be reduced by a further sixty seconds to four minutes, and players will be instructed to use a towel rail at the back of the court.

It is hoped this will further speed up play, and reduce the onus on the ball boys and girls to fetch and handle the players’ sweaty towels.

Staging two competing World Cup events in the space of six weeks would be “insane”, says ATP executive chairman Chris Kermode.

The International Tennis Federation has set out plans for an 18-team end-of-season event which will crown the Davis Cup champions from 2019.

The ATP’s priority is to stage a revamped World Team Cup in Australia in the first week of January from 2020.

“Hopefully tennis works together and we come up with a solution,” said Kermode.

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• ATP likely to introduce 25-second shot clocks and reduced warm-ups

Talks have already taken place between the ITF – the governing body of world tennis – and the Association of Tennis Professionals to try and find a compromise, he added.

Kermode, whose organisation runs the men’s professional tour, says he is “confident” there will ultimately only be one World Cup, but cannot promise it will be a co-sanctioned event.

“It doesn’t make any sense to have two team events. Personally I think that would be insane. Let’s just hope that doesn’t happen,” Kermode told BBC Sport.

“We have had very, very good talks. What we are trying to do is understand that tennis is a multi-faceted business. Davis Cup is a sports entity that has been around for hundreds of years and we value it.

“Equally the World Team Cup was an event we had for 35 years. It’s been off the shelf for a while, but could we bring that back?

“I think there’s clearly a demand for a huge team event that anyone can buy into.”

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British number one Kyle Edmund continued his fine run of form with a hard-earned round one win over Malek Jaziri at the Italian Open.

The world number 19 saved break points in his opening service game but beat the Tunisian 6-3 3-6 6-3.

Edmund moved inside the world’s top 20 for the first time on Monday after reaching the quarter-finals of last week’s Madrid Open.

He now faces either Lucas Pouille or Andreas Seppi in round two in Rome.

Edmund, 23, beat Novak Djokovic on his way to the quarter-final in Madrid and he continues to look most comfortable on clay.

But Jaziri, 34, was also in confident mood having reached the final of the Istanbul Open last month.

The world number 64 pressured the Briton in the first game but Edmund broke his rival to take a 4-2 lead and closed out the set.

Jaziri broke in the fourth game of the second set and went on to level but Edmund produced the solitary break of the decisive set.

Djokovic – now just one place above Edmund in the global rankings – overcame Alexandr Dolgopolov in straight sets earlier on Monday to also reach round two.

World number two Caroline Wozniacki was stunned by Kiki Bertens in the third round at the Madrid Open.

The Dane could have overtaken Romania’s Simona Halep as world number one by winning the tournament, but was beaten 6-2 6-2 by Dutch world number 20 Bertens in just 61 minutes.

Bertens will now face five-time Grand Slam champion Maria Sharapova.

The Russian, who dropped out of the world’s top 50 last month, beat France’s Kristina Mladenovic 6-3 6-4.

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Defending champion Halep had earlier registered a straightforward 6-1 6-4 win over Czech Kristyna Pliskova to reach the quarter-finals.

Halep barely looked troubled as she won five consecutive games to clinch the opening set in 29 minutes.

Pliskova produced a better second set but she could not maintain any pressure, with Halep saving all five of the break points she faced.

She finished with 32 unforced errors to Halep’s 13 as her opponent closed out victory in 77 minutes.

Halep will face sixth seed Karolina Pliskova – twin sister of Kristyna – after she knocked out American Sloane Stephens 6-2 6-3.