On the report below from BBC Sport on Andy Murray's win in Miami last night it mentions an incident where Murray picked up a ball from the women's event. I never knew they used a different sized ball in women's tennis than they do in the men's.



Britain's Andy Murray and Heather Watson both progressed at the Miami Open on a day when players struggled in the heat.

Murray played in cooler temperatures as he beat Uzbekistan's Denis Istomin 6-3 7-5 in the evening session.

Watson had earlier fought back to beat Belgian Yanina Wickmayer 3-6 7-5 6-3 over two-and-a-half hours.

Fellow Briton Aljaz Bedene was forced out with a wrist injury, while Jamie Murray lost in the doubles.

Having waited until the final session of day six to play his first match, second seed Murray saw off world number 76 Istomin in one hour and 38 minutes.

There was a moment of confusion in the second set when Murray found himself serving with a rogue ball from the women's event, and duly dropped serve.

"The women's balls are very different from the men's balls," he said.

"They're much quicker, smaller, livelier, and when you're just about to serve at break point down, you don't want to be using a completely different ball. So I was just a bit frustrated with that."

Murray broke straight back in the following game on his way to setting up a match against Bulgarian 26th seed Grigor Dimitrov in round three.