What to watch at US Open: What if coaches played?

FEDERER VS. CILIC: Federer leads 5-0 head to head, but he needed to save six match points in the second set in the most recent one, on a hard court in Toronto last month.
   
"That's maybe exactly the kind of matches I needed to win," said Federer, who already owns a record 17 Grand Slam titles, including five at the U.S. Open.
   
He is coming off a dramatic comeback in the quarterfinals, fending off two match points and climbing out of a two-set hole to edge Gael Monfils 4-6, 3-6, 6-4, 7-5, 6-2.
   
Cilic will be participating in his second major semifinal and first since 2010; he's the first man from Croatia to make it that far at Flushing Meadows since Ivanisevic in 1996.
   
Cliic missed last year's U.S. Open while serving a doping suspension that later was reduced to four months on appeal.
 
 "I feel," Cilic said, "I'm playing probably the best tennis of my career."