LONDON (AFP) - South Africa's Kevin Anderson hit out at social media haters for targeting him with death threats after he lost in the first round at Wimbledon.

The 30-year-old, Africa's only player in the world top 50, slumped to a 4-6, 6-7 (13-15), 6-4, 7-6 (7-2), 6-3 defeat by Denis Istomin of Uzbekistan.

"Bummed to have lost yesterday, but at least I had a ton of death threats on facebook and twitter to make me feel better about things...," tweeted Anderson.

"Thanks to GOOD people out there who stick with me through this tough year. My #Wimbledon is done, looking forward to US Hardcourt Season."

Anderson reached a career high of 10th in the world last year but this season has seen him plagued by knee and elbow injuries.

The Florida-based player has won just five matches all year.