Just a week on from the reopening of the debate around equal pay in tennis, Andy Murray found himself at the centre of another gender-related tennis issue over the weekend.

Murray has been a big advocate of equality in the sport, but on Saturday he was enraged when he was mistakenly given a tennis ball from the women's tour to use during his second-round win against Denis Istomin at the Miami Open.

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The world No.2 confronted umpire Mohamed Lahyani and said: "That's one of the women's balls and I could have hit a shot with it."

At the next change of ends, Murray continued: "For me that's not good enough, it's unacceptable. Unacceptable to have one of those balls in there."