The world number one tried “a spoonful” of food meant for her dog Chip before beating fellow American Christina McHale in straight sets in Rome.

“I thought ‘what the heck, I’m gonna try a piece, it looks good’,” said the 34-year-old.

“Fast forward two hours – I just ran to the toilet like I thought I was going to pass out.”

In a video posted on Snapchat before her match with McHale, Williams explained she sampled a dish of chicken and rice offered on a ‘doggy menu’ at her hotel.

“It did taste weird,” she said. “I force-swallowed it. It tasted kind of like house cleaner. I don’t know what they put in these dog foods, but Chip liked it.

“I don’t think it’s consumable for humans – they should have wrote that! So now I feel really sick. It was just a spoonful but I don’t feel so good.”

Williams recovered in time to defeat McHale 7-6 (9-7) 6-1 and set up a meeting with Svetlana Kuznetsova – who beat fellow Russian Daria Gavrilova – in the last eight.

Serena, the world’s top women’s tennis player, was named Laureus World Sportswoman of the Year again, after a sparkling 2015 in which she won three Grand Slams.

Laureus Academy Member Boris Becker, now Djokovic’s coach, said: “He had a great year again. He’s played 88 matches, has won 82, He won three out of the four Grand Slams, reached the final of the French Open, he’s won seven other tournaments. Very few players, if any, had a year like that.”

There was a special posthumous Laureus Spirit of Sport Award to celebrate the life of Johan Cruyff, who died in March. It was received by his son Jordi Cruyff.

On a glittering evening in Berlin that recognised the outstanding sporting achievements of 2015, rugby was the other big winner with the All Blacks taking the Laureus Team Award and Dan Carter receiving the Laureus Comeback of the Year Award, following the team’s Rugby World Cup success.

Carter said: “It’s nice to be recognised for the year I had in 2015. It was a very special year, not only for me, but also for the All Blacks and to be a part of that was amazing.”

To the delight of the Berlin audience, Germany’s Jan Frodeno, the first man to win both the Ironman World Championship and an Olympic triathlon gold medal, was presented with the Laureus Action Sports Award, while golfer Jordan Spieth won the Laureus Breakthrough of the Year Award. Spieth said: “Thank you so much to the Laureus Academy. Just to know a couple of you is an honour. For me it’s unique. We’re used to being recognised in the golfing community but this Award recognises us around the world to all of sport and it’s something that’s very difficult to put into words.” Brazilian Paralympic swimmer Daniel Dias won his third Laureus Disability Award, another record. Dias, who is one of Brazil’s big hopes for gold medals the Paralympic Games in Rio de Janeiro in September, said: “This is another great honour for me and gives me great encouragement, as we are now in the build-up to the Paralympic Games in Rio. To think I have won win three Laureus Awards, something only managed by other sportsmen like Roger Federer, Usain Bolt and Kelly Slater, is quite overwhelming.”

Three-time Formula One world champion Niki Lauda, now Non-Executive Chairman of the Mercedes AMG Petronas team, received the Laureus Lifetime Achievement Award.

Serena Williams fired a warning to Maria Sharapova ahead of their Wimbledon semi-final clash as the world number one admitted she saves her best performances for clashes with her fiercest rival.

Williams and Sharapova meet on Thursday in the latest instalment of a bitter rivalry that took root on Centre Court in 2004 and still festers more than a decade later.

Sharapova caused one of the great Wimbledon shocks 11 years ago when, aged just 17, she defeated Serena in the final to claim her first Grand Slam title.

The duo’s relationship has remained frosty ever since, occasionally turning nasty — as it did when they traded barbs about Sharapova dating Williams’ ex-boyfriend Grigor Dimitrov and the American’s own relationship with her French coach Patrick Mouratoglou.

But, while Sharapova has collected five Grand Slam titles and built a global brand that makes her the world’s highest paid female athlete, the 28-year-old has still been left trailing in Serena’s wake and the Russian hasn’t come out on top since 2004.

The 33-year-old American has a 17-2 lead in their head to head record, winning their last 16 meetings and depriving Sharapova of three major titles — in the 2007 and 2015 Australian Open finals and the 2013 French Open final.

Serena has also won all four of her semi-final meetings with Sharapova, defeated the Russian in their previous Wimbledon clash in the last 16 in 2010 and routed her in the 2012 Olympic final at the All England Club. After battling back to defeat Victoria Azarenka 3-6, 6-2, 6-3 in the last eight — extending her winning run at Grand Slams to 26 matches and her 2015 record to 37-1 — Serena can’t wait to take on Sharapova again. “I love playing Maria. I think she brings out the best in me. I thought we had a wonderful final in Australia. It was very entertaining,” said Serena, who remains on course to hold all four major titles at once and is in the hunt to clinch the first calendar Grand Slam since 1988.

“For me, I don’t feel like I have any pressure going into this match.

“It’s just totally different for me. I don’t have anything to prove. I won all the Grand Slams, multiple times. Now it’s just I’m here just to enjoy it.

“It’s actually making me play better, which is crazy.”

– New match -Sharapova is in her fifth Wimbledon semi-final, and her first since 2011, thanks to a hard-fought 6-3, 6-7 (3/7), 6-2 last eight victory over Coco Vandeweghe.

Asked if her lack of success in the Serena match-up would be weighing on her mind, Sharapova gamely insisted she still relishes the challenge of playing the American.

“I think it’s always a new match. I haven’t had great success against her. I would love to change that around. That’s how I look at it,” the world number four said.

“Definitely no secrets between each other’s games, but it will be an incredible moment for me to step out on Centre Court against her again.

“If you look at Grand Slam champions, you look at their draws, everyone comes from a few challenges, being down in matches. “There’s no easy road to victory. You’re going to have your bumps. That’s the way I see it.”

The other semi-final may end up being overshadowed by Serena v Maria Part 20, but there is still plenty of intrigue in the meeting between Agnieszka Radwanska and Garbine Muguruza. Radwanska defeated Madison Keys 7-6 (7/3), 3-6, 6-3 to reach her fourth Grand Slam semi-final and her third at Wimbledon.

The Polish 13th seed reached the Wimbledon final in 2012, losing to Serena, and she hopes her experience of the latter stages of a major will stand her in good stead against Spanish 20th seed Muguruza, who will be appearing in the last four of a Grand Slam for the first time.

Williams has swept to Australian and French Open triumphs over the last six months and the world number one returns to the All England Club within two major titles of becoming the first woman since Steffi Graf in 1988 to claim the four top titles in one year.

The 33-year-old American also won the US Open to end 2014 on a high and is heavy favourite to continue that dominant run by taking the Wimbledon title for the sixth time in her illustrious career.

Her march to a momentous milestone has captured the public’s attention and Serena knows the eyes of the sporting world will be on her over the next fortnight.

But she insists she will have no problems with the extra attention and expectation because her mental toughness is a bigger strength than even her booming serve and over-powering groundstrokes.

“Personally it doesn’t make it feel any different, which I think is a good thing because I don’t feel any pressure to win all four,” Williams told reporters at Wimbledon on Saturday.

“I really don’t feel that pressure. Maybe if I would happen to win here, then maybe I might start feeling it after that.

“But for me being mentally tough is probably my biggest strength.

“Being the youngest of five children really made me have to scrap and be tougher.

“It’s great to have a big serve, too. Ultimately you could be the best player in the world, but you still get down and you have to be able to come back.”