PORTLAND: Nike, TAG Heuer and Porsche have all suspended their sponsorships of Maria Sharapova after the five-time Grand Slam tennis champion admitted failing a drug test.

Sportswear giant Nike, partway into a $70m eight-year contract, said it was “saddened and surprised” at her admission that she tested positive for a banned substance at the Australia Open in January.

A statement added: “We have decided to suspend our relationship with Maria while the investigation continues. We will continue to monitor the situation.”

Swiss luxury watchmaker TAG Heuer, which has had a relationship with Sharapova since 2004, said it had stopped negotiations with the player, whose previous contract ended on December 31.

A spokeswomen said: “We had been in talks to extend our collaboration. In view of the current situation, the brand has decided not to renew the contract with Sharapova.”

Porsche, which signed a three-year-deal with Sharapova to become their first female ambassador in 2013, also said it would be suspending promotional work with the player.

The company explained: “We are saddened by the recent news announced by Maria Sharapova. Until further details are released and we can analyse the situation, we have chosen to postpone planned activities.”

The Russian, who lives in Florida, has been linked with Nike back to when she was 11 years-old. She is the world’s highest paid female athlete after earning nearly $30m in 2015 from winnings and endorsements.

Nike has lately taken a much sharper approach with athletes who risk bringing reputational damage aboard.

It has severed ties with cyclist and drugs cheat Lance Armstrong as well as sprinter Oscar Pistorius and, last month, dropped Manny Pacquiao after the boxer said homosexuals were “worse than animals”.

However Nike clearly works on a case-by-case basis since it has stood by Tiger Woods, Kobe Bryant and multiple drug cheat Justin Gatlin.

Hence the Sharapova deal has been suspended and not scrapped.

She has admitting to having tested positive for meldonium, a substance she claims she has been taking since 2006 for health issues. The International Tennis Federation (ITF) said she would be provisionally suspended from March 12.