Tension between Americans Serena Williams and Sloane Stephens is expected to intensify after footage emerged of what appeared to be Stephens celebrating Williams' shock exit from the Australian Open.

The pair have not seen eye to eye since Stephens knocked Williams out of last year's Australian Open quarter finals, with Stephens later taking aim at the world No.1 for unfollowing her on Twitter.

Stephens also accused Williams of ignoring her after she defeated the now 17-time grand slam champion at Melbourne Park last year. Their relationship has remained fractured.

Taking pleasure in Serena's pain: Sloane Stephens.

Taking pleasure in Serena's pain: Sloane Stephens. Photo: AFP

It doesn't seem those wounds will heal any time soon after Stephens was caught with a smile from ear to ear as Williams' Australian Open campaign came to a crashing halt at the hands of Ana Ivanovic on Rod Laver Arena on Sunday afternoon.

It looked like happiness to see her compatriot bundled out of the tournament, but Channel Seven later tried to smooth the situation by insisting Stephens was only impersonating the celebrations of Ivanovic's support crew.

Regardless of whether she was making a joke or laughing at Williams' expense, Williams may well take it as another shot from the confident 20-year-old.

Channel Seven showed the vision during the coverage of Casey Dellacqua's match against Eugenie Bouchard.

The last time the pair met was in the US Open last year, with Williams wiping the court with Stephens on Arthur Ashe Stadium for a 6-4, 6-1 victory.