The former Manchester United boss beamed with joy from the Royal Box and appeared to say "that was good" after Murray secured a straight sets victory over Kevin Anderson.
Speaking immediately after the match, Murray said: "That was a good win because he was playing very well at the end, making it very tough."
Meanwhile an online naming row appears to have broken out between British tennis supporters.
The area where fans at the All England Club watch Wimbledon on a giant screen was originally called Henman Hill, after English player Tim Henman. On the Google maps site, it was renamed Murray Mound after Murray won the title last year, but in the past two days the name was changed back - possibly by a disgruntled Tim Henman fan.
A spokesman for Google said the changes were being made by users of its Map Maker app.