
It's tough being a tennis pro -- and the game's high profile brings great scrutiny on social media. US player Nicole Gibbs says she started receiving offensive online messages from as young as 17.

"I hope you die slowly," one Twitter user told Gibbs after her first-round defeat at the Moscow Open in 2016 -- an insult the 90th-ranked American labeled an "epidemic."

"In-play betting" and opportunities to gamble on almost every game, set and match means players across the game are being put under increasing scrutiny by punters. Gibbs is by no means alone ...

At the age of just 22, Canadian Rebecca Marino was forced to quit tennis following a battle with mental illness. She says this struggle was worsened by online abuse.

The top-ranked players are also attacked by so-called "keyboard warriors." American world No. 8 Madison Keys tells CNN that "people wish horrible things on your family and everything because they are betting on tennis."

Keys also spoke out against Twitter's treatment of the abuse. "Half the time you report them to Twitter and nothing happens ... Or they just make a new account," the former Australian open semifinalist said. Twitter said it focuses on: "Controls, reporting, and enforcement."

Eugenie Bouchard, runner-up at Wimbledon in 2014, is determined to see the positive side of online abuse: "Everyone out there has haters," she said, "I try to see it as motivation."

Men are subject to abuse, too. Big-serving Australian Sam Groth said last December that his family and girlfriend receive death threats after some matches.

Former top-10 player Kevin Anderson of South Africa said he received a torrent of online abuse and threats after losing his first-round Wimbledon match in 2016, when he blew a two-set lead.