Serena Williams, Li Na advance to round three in the heat

Serena Williams said her method for dealing with the head was to simply avoid long rallies.
Chris Hyde/Getty Images

Copyright 2014 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

SI Apps
We've Got Apps Too
Get expert analysis, unrivaled access, and the award-winning storytelling only SI can provide — from Peter King, Tom Verducci, Lee Jenkins, Grant Wahl, Andy Staples and more — delivered straight to you, along with up-to-the-minute news and live scores.