She roared him on to victory as he made it through to the quarter-finals yesterday, but his matches are still painful viewing for his mother.
When asked if sitting in the players' box was less stressful than last year, she said: "No! I think there is a huge expectation level out there from everybody, obviously because he's won Wimbledon and he's won the US Open and the Olympics.
"I think everybody is expecting him to do well."
Mrs Murray, who was speaking at the launch of the Miss Hits programme which encourages young girls to play tennis, added that her son has the experience to win it all again.
"It's a very, very tough sport. The strength in depth in the men's game is enormous," she said.
"But he's been playing at Wimbledon since 2005, he knows what to expect. He's always handled it really well and he's 27 now, he's older, more mature. He'll be out there trying to do it all again."
Murray's next opponent is Bulgarian Grigor Dimitrov, whose girlfriend is Maria Sharapova.
The Scot is heavily favoured with odds of 2/7 to win.
A spokesman for bookmaker Paddy Power said: "Whilst we're all for a bit of cupid love out on the courts, we're hoping that Murray rains on the Dimitrov and Sharapova parade and drenches their hopes of Wimbledon success."
Sharapova is in action on Centre Court today and is expected to be watched from the Royal Box by operatic singer Katherine Jenkins and her fiance Andrew Levitas, travel writer Bill Bryson, celebrity chef Michel Roux Jr and newsreader Fiona Bruce.
The last two days of action of SW19 were disrupted by wet weather, but spectators basked in glorious sunshine as the action got under way today.
Forecasters at the Met Office predict a dry day with a maximum temperature of 21C (69.8F).