Andy Murray has admitted he is suffering from a lack of confidence for the first time in his tennis career. The Brit again crashed out of the first round of a tournament on Tuesday, exiting the Marseille Open at the earliest opportunity. Murray is now winless in his last six singles matches and has exited in the first round in the last five competitions he has entered. Czech star Tomas Machac piled more misery on the two-time Wimbledon champion with a straight-sets win in Marseille. Murray has already said 2024 could be his final year in professional tennis and fans called on him to retire aft…