Last American US Open champ Andy Roddick shares advice for Coco Gauff, Ben Shelton

Andy Roddick has some advice for American tennis stars Coco Gauff and Ben Shelton ahead of their toughest matches of the U.S. Open tournament: Don't listen to "dummies like me on TV."

OK, those weren't the only words of wisdom shared by the 41-year-old former tennis professional on "Good Morning America" Friday morning, but in Roddick's own experience -- especially as the last American man to take the U.S. Open title in 2003 -- he did say that as the pacing becomes easier, they should "use the day off to rest and maybe work on just a few things."

Gauff, the 19-year-old tennis phenom, is headed to her first U.S. Open final after her 6-4, 7-5 semi-final victory Thursday night over Karolína Muchová -- despite a nearly 50-minute delay that sent both players off the court early in the second set.

"I think it's an imperfect scenario," Roddick said of the climate change protestors whose demonstration disrupted play (two protesters were arrested Thursday night and charged with criminal trespass, after both began shouting and one allegedly glued his feet to the concrete floor in the stands). "I think for Coco, she said I'm just going to treat it like a rain delay -- you don't know if it will be 10 minutes or an hour and a half -- obviously, she handled it as well as you could."

He commended Gauff for her poised performance saying, "She's just been amazing this summer, winning in D.C., winning in Cincinnati and marching right to the U.S. Open finals. She is a star. She is exciting. She's an awesome person, too."

Roddick acknowledged her "heavy work load" entering the Open in all three events: mixed doubles, doubles and singles.

"Maybe be practice-specific about her next opponent Aryna Sabalenka, who is just full of power and will try to go through Coco on Saturday. I think just more of the same. I don't think you change too much up," Roddick imparted. "She's been on such a good run this summer -- partnering with [coach] Brad Gilbert post-Wimbledon has been a really good move for her."

All in all, for Gauff, Roddick said he thinks "it's just going to be a matter of how she handles the moment."

Fellow American singles player Ben Shelton, meanwhile -- the unranked star who upset No. 10-ranked Frances Tiafoe in the quarterfinals Wednesday -- will take on three-time U.S. Open champ Novak Djokovic, who is also coming off a hot streak this summer.

For 20-year-old Shelton, who is from Atlanta, Georgia, and who is just one year younger than Roddick was when he won the U.S. Open title in 2003, the former champ suggested, "He can't be subtle with anything."

"I talked to Ben's father yesterday on the phone. I said, 'There's no red light, there's no yellow, it's green light the whole way. He's gotta try to go through Djokovic,'" Roddick said. "Novak's superpower is finding a pattern he wants with direction. He's like a surgeon out there. You don't want Novak to know what's coming."

"He's got to mix up the pace and speed on first and second serves, not let Novak get the same look five or six times in a row. Try to make it about a couple of points here and there," Roddick added. "Don't be scared to come in on a bad shot. What you need to do is just put the thought of it in Novak's head. Novak's a cyborg with the way he goes about his business. You can't go around him, you can't go through him. You're going to have to mix it up."

Even with 20-year-old Carlos Alcaraz of Spain -- who is playing Daniil Medvedev in the other men's semifinal Friday evening -- coming off his recent Wimbledon title and vying for a repeat on American soil to follow his first Grand Slam last season, Roddick said he has "a hard time betting against Novak in a three out of five set format."

"I think he's the best player of all time. Statistics would agree," Roddick said.

He added, however, "Alcaraz is the guy with the upside, he's probably my favorite player to watch on earth right now. He reminds me of Lebron James -- he is one of the most exciting guys I have seen in a long time."