Serena Williams' coach Patrick Mouratoglou believes the American needs to change her strategy in matches if she is to break the all-time Grand Slam singles record.

The 38 year-old currently has 23 titles to her name, one behind Australian Margaret Court.

But Williams has not won a Slam title since January 2017 and has lost her last four finals, something Mouratoglou sees as a sign of things needing to evolve.

Speaking to BBC Sport, he said: "We have to accept the fact that it is not working. Maybe come back with a different angle, a different strategy and different goals so she can make it.

"She does feel positive, she feels negative too because it is a failure when she doesn't win a Grand Slam.  We have to face reality, but she is positive that she can make it otherwise she probably wouldn't be on a tennis court anymore.

"She believes she can make it and I believe it too. She's not that far, but we have to change a few things."

Williams missed four Grand Slam events from the 2017 French Open to the 2018 Australian Open in order to give birth to her daughter Olympia in September 2017.

However, after becoming a mother, many questioned whether she would return to the court and if he did whether or not she would be the same player.

But just ten months later, Williams was remarkably already back in a Slam final at Wimbledon, only to be beaten by Angelique Kerber.

"She had everything to retire, 23 Grand Slam titles," added Mouratoglou. 

"But she decided to come back, she decided to make all the efforts, the physical efforts, the mental efforts, to come back to the game, with the goal to score more Grand Slams and beat the all-time record.

"It's difficult to know how many chances she will have, I don't know how long she is going to be able to play, but being able to reach four Grand Slam finals says a lot about her level, and she's not that far.

"Her level is good enough but we have to understand what is going on and why she is not able to win one. There is a big difference between reaching a final and winning one."