Defending champ Andy Murray gets by Fabio Fognini to reach last 16

Andy Murray did not play his best against Fabio Fognini but he's through to the fourth round at Wimbledon.

There’s a reason why top players like the best-of-five format. The underdog can get hot for an hour—or the favorite’s level can drop for a stretch—and there’s ample time for a market correction. A longer match = a greater sample size = a greater chance of a regression to the mean.

We got a vivid display of this principle on Friday evening on Centre Court. Andy Murray did not play his best against Fabio Fognini. He lost the second set 6-4. He trailed 2-5 in the fourth. But with the cushion of a longer match, Murray had time to find his game and the better player won.

Happy with his fight if not his form, Murray took it 6-2, 4-6, 6-1, 7-5. The defending champ gets Benoit Paire next in the fourth round.