Serena Williams' hopes for a calendar Grand Slam are still alive. But it took three hard-fought sets to beat her sister Venus 6-2, 1-6, 6-3 and reach the US Open semifinals.

The seven-time Grand Slam champion only began her tennis comeback last month, when she played the Citi Open in Washington, ...

Still, USPTA Hall of Famer and Serena Williams's former coach Rick Macci warned how things might "get worse" for the 21-year-old due to some flaws in her game.