Sarah Sjostrom’s 100m freestyle entry poses huge Paris Olympics challenge for Mollie O’Callaghan

Sarah Sjostrom caused a shock when her name appeared among the 100m freestyle entrants for the Paris Olympics — and it could have a huge impact on Australia’s big gold medal hope.

The woman who provided an Aussie great a shoulder to cry on in her Olympic moment of need could be the one to cause tears for an Australian world champion at the Paris Games.

Swede Sarah Sjostrom, one of the greatest sprinters in swimming history, has been confirmed as an entrant in the 100m freestyle in Paris after initially saying she would only contest the 50m

It’s significant given the Swede remains the world record-holder in the event, meaning Australia’s world champion Mollie O’Callaghan will have to overcome the best in history in both her individual events — the 100m and 200m freestyle — if she is to snare Paris gold.

Sarah Sjostrom has been confirmed as an entrant in the 100m freestyle in Paris. Picture: Getty Images

It’s difficult to paint Sjostrom as the enemy though.

The now 30-year-old was one of the first to console great friend and rival Cate Campbell after she missed the medals in the 100m freestyle in Rio, even as she had won her own bronze in the event.

Campbell had gone into the race as the hottest of hot favourites but faded to miss the medals completely and finish in sixth place.

Devastated and in her own words, ashamed, at having what she perceived at the time as her failure, Campbell was immediately consoled by Sjostrom and Denmark’s Jeanette Ottesen.

“We are friends… I always want to support her,” Sjostrom told Australian reporters of her reaction at the time.

“If you can see someone that is so disappointed, you want to go and say something and put your hand on their shoulder.

“Usually she is happy all the time … she is always smiling.”

Sarah Sjostrom remains the world record-holder in the 100m freestyle. Picture: Getty Images

A champion butterflier and sprint freestyler, Sjostrom holds the world record in the 100m freestyle and is one of only two women in history — along with Emma McKeon — to have broken the 52sec barrier in the event.

She also holds the 50m freestyle world record — and eight of the top 10 times in history — and while she has won four world championships in that event, she has not won an Olympic title in either freestyle discipline.

A freak accident ahead of the Tokyo Olympics, where she slipped on ice and broke her elbow just over five months out from the Games, led to her racing at reduced capacity after an operation to insert screws and a plate in her arm, while in 2016 she was rated one of the favourites, along with Campbell but had to settle for bronze behind Canadian Penny Oleksiak and America’s Simone Manuel, who tied for gold.

While it was a shock to see her name among the 100m entrants for Paris given her assertion she would concentrate solely on the 50m, there were few who thought Sjostrom wouldn’t at least enter the event which could be described as the unfinished business of her career.

Sarah Sjostrom and Mollie O'Callaghan will go head to head at the Paris Olympics. Picture: AFP

Sjostrom’s entry, along with the presence of Dutch woman Marrit Steenbergen, who with a time of 52.26sec is the fastest in the world this year, and Hong Kong’s Siobhan Haughey, whose 52.02 last year was one of the quickest in history, is a massive challenge for O’Callaghan.

If anything though, it should take pressure off the young star, who despite being an Olympic gold medallist and three-time world champion will tackle her first individual Games events in Paris.

After Ariarne Titmus took her 200m world record at the Australian Olympic trials, O’Callaghan may not be favourite in either event.

But that may actually be a better option for the 20-year-old, who has detailed just how nervous she becomes ahead of major events.

O’Callaghan is back to being the chaser — and that’s just the way she likes it.