Nobody in tennis is surprised by Andy Murray's split from coach Amelie Mauresmo, says Serena Williams' coach Patrick Mouratoglou.
British two-time Grand Slam winner Murray, 28, and Frenchwoman Mauresmo, 36, mutually ended their two-year working partnership on Monday.
"Everyone knows everyone in the lockers rooms and players lounges," said Mouratoglou, who has coached Williams to eight Grand Slams since 2012.
"Obviously something was wrong."
Mouratoglou pointed to Mauresmo not being in the players' box at the Miami Open in March, where the Scot went out in the third round while making 55 unforced errors against Grigor Dimitrov.