Fans have accused a sports commentator of comparing Venus Williams to a "gorilla".

Tennis fans are calling for sports commentator Doug Adler to be sacked for a comment made during Venus William’s second-round match at the Australian Open.

Viewers believe the 59-year-old former tennis pro, who is currently employed by U.S. television station ESPN, compared the world number 17’s on-court pressure to that of an ape.

“She misses a first serve and Venus is all over her,” Adler said. “You see Venus move in and put the gorilla effect on. Charging.”

One of those enraged by the statement is New York Times tennis journalist Ben Rothenberg, who described the comment as "appalling stuff".

“Horrifying that the Williams sisters remained subjected to it still in 2017," he tweeted.

Many others agreed.

"Doug Adler's said some awful things in the commentary booth before, but this is next-level disgusting," fellow tennis writer Victoria Chiesa wrote.

While Adler nor ESPN have spoken on the rogue comment, others were confused by the furore, explaining they interpreted Adler's description as “guerrilla”.

"Maybe he meant "guerrilla effect", as in warrior charging?" one viewer suggested.

"I was listening to this feed and it did not come across as a racial epithet."

Reportedly, Adler later apologised while commentating the mens Escobedo-Ferrer match, saying he was sorry for the confusion caused, clarifying he was referring to the term "guerrilla warfare".