Andy Murray DOMINATES First Post-Wimbledon Tennis Opponent

So ... when Andy Murray's girlfriend agreed to play the Wimbledon champ in a game of smash ball on the beach this week ... think she felt a tad bit inadequate?

26-year-old Murray and his 25-year-old GF Kim Sears celebrated his big Wimbledon victory with a beach trip to the Bahamas ... and the first order of business -- beach tennis.

Meanwhile, Andy's top Wimbledon opponent, Novak Djokovic, was last seen at a village in Serbia ... riding a tractor.

Murray wins. Again.