Alastair Cook completed a number of notable achievements with his superb double-hundred in the fourth Ashes Test, but one surprising statistic may have slipped under the radar of many observers.

Read: Cook gives England control at MCG

Unbeaten on 244 at the end of day three, England opener Cook is now responsible for the highest score by a visiting player at the MCG and has moved up to sixth on Test cricket's all-time run-scoring list, overtaking Mahela Jayawardene, Shivnarine Chanderpaul and Brian Lara in one innings.

He is also only the second England player to reach 200 twice in a calendar year, after Wally Hammond, and those twin double-tons mean Cook's recent batting average is not what you might expect.

Read: The Ashes Round-up: Cook a class apart as England claims huge lead

Despite managing a high score of just 37 in 10 innings prior to this week's Test, Cook's average in his last 12 knocks is now an impressive 57.

It's amazing what a couple of innings spanning more than 400 deliveries will do to your statistics.