At the start of December, Betfair exchange had his back price to win the Australian Open at $2.30 and his lay price at $2.36. At the start of January, he had come into $2.10 and $2.12 to ay. This morning he was $1.94 to back and 1.98 to lay. 12 hours later he is $2.10 to back and $2.16 to lay.
This is quite unusual for an exchange. His price actually came in after losing to Karlovic, and now his price is back out again on the back of absolutely nothing??
This might be worth keeping an eye on if you like to trade.