NEW YORK -- At 19, Jared Donaldson is the youngest American man in the U.S. Opens third round since 2007. A key part of his growth as a tennis player happened in another country, though.When he was 14, Donaldson left home to train in Argentina, so he could work on his game on clay, improve his footwork and get lessons on how to use spins on his shots.He learned more, too, during the 2 1/2 years he was there.The biggest takeaway from me in Argentina was how focused and dedicated those guys were training. They were so serious. I think it was really eye-opening for me. The fact that they work so hard, even when they were tired. Clay court is so physical, said Donaldson, who is ranked 122nd and got through qualifying to reach the main draw at Flushing Meadows. It put me in a pro mentality when I was very young.Heading into Saturdays third-round match on Court 17 against 21st-seeded Ivo Karlovic of Croatia, Donaldson already has enjoyed the best week of his nascent career. Not only did he collect the first two Grand Slam victories, but they came against a couple of established players, 12th-seeded David Goffin of Belgium in the first round and Viktor Troicki of Serbia in the second.And even if other U.S. teens have drawn more attention recently -- a pair of 18-year-olds, Taylor Fritz and Frances Tiafoe come to mind -- Donaldson has big things in mind.I want to be top 10, top 5, No. 1. Eventually, if I get to that ranking, Ill have enough attention, almost too much attention, he said. I just have to make sure that I stay focused on my game, try not to let the outside factors kind of dictate how I play or act. I just have to keep improving.To that end, he started working with former pro Taylor Dent as his coach, initially aiming to serve better. But Donaldson credits Dent -- and his father, Phil, also a former player -- with improving other aspects of his play, also.All the kind of things Im doing out there now is a reflection of (Taylors) influence on me, coaching with me, working with me, Donaldson said. I owe a lot to him.Karlovic will present a challenge when it comes to returning serves: The 6-foot-11 Croatian, who beat American Donald Young in the second round, set a U.S. Open record with 61 aces in his first-round match Tuesday.Here is what else to watch Saturday at the U.S. Open:WILLIAMS SISTERS: Once again, both Williams sisters will be in action on the same day -- and in the same arena, Arthur Ashe Stadium. No. 1 seed Serena Williams goes first, facing 47th-ranked Johanna Larsson of Sweden in the afternoon. No. 6 Venus Williams plays at night against No. 26 Laura Siegemund of Germany. While Serena is bidding for a record 23rd Grand Slam singles title, and Venus owns seven, neither Larsson nor Siegemund ever has been as far as the fourth round at any major.KYRGIOS IN SPOTLIGHT: In the final match under the lights in Ashe, 14th-seeded Nick Kyrgios gets his chance on center stage, facing 63rd-ranked Illya Marchenko of Ukraine. Kyrgios is among the most talented -- and moody -- men on the tennis tour, as likely to hit a `tweener as fantastic as Rafael Nadals from Friday as he is to throw a racket or appear to give up mid-match.MURRAY VS. LORENZI: As 2012 U.S. Open champion Andy Murray tries to become the fourth man in the Open era, which dates to 1968, to participate in all four Grand Slam finals in one season, he takes on Italys Paolo Lorenzi, who is ranked 40th and will be playing in a third-round match at a major for the first time.---Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrichMattias Ekholm Jersey .C. -- Chris Thorburn thinks one of the reasons the Winnipeg Jets have been successful under new coach Paul Maurice is that theyre playing together as a team. P. K. Subban Jersey . In taking its goal tally to 99 in all competitions already this season, City delivered another demonstration of its lethal firepower at Etihad Stadium to set up a fourth-round match at home to another second-tier team -- Watford. http://www.cheappredatorsjerseyschina.com/viktor-arvidsson-jersey/ .Y. - Detroit goaltender Jonas Gustavsson has earned NHL first star of the week honours after winning in his first three appearances of the season. Matt Irwin Jersey . Jane Virtanen scored two, and Alex Roach and Elliott Peterson rounded out the offence for the Hitmen (40-15-6). Brady Brassart chipped in with three assists. Colton McCarthy scored twice, Brayden Point had a goal and two assists, and Jack Rodewald also scored for the Warriors (15-35-9), who were 2 for 5 on the power play. Filip Forsberg Jersey . -- New England Revolution goalkeeper Matt Reis is retiring after a 16-year career to become the goalie coach for the Los Angeles Galaxy.CLEVELAND -- The Washington Nationals have reinstated first baseman Ryan Zimmerman from the disabled list after he missed 13 games because of a strained left rib cage.Zimmerman recently completed a rehab assignment at Single-A Potomac, where he batted .417 (5 for 12) with a homer and five RBI. Zimmerman was batting only .221 with 12 homers and 38 RBI for Washington when he got hurt.Although he hasnt hit for a high average, the 31-year-old Zimmerman has been clutch -- 12 of his RBI have given the Nationals the lead or been game-winners.Hes battting seventh and playing first in Tuesdays game against the Indians.ddddddddddddAlso, the team reinstated left-hander Sammy Solis, who was sidelined 13 games because of an inflamed right knee. The 27-year-old has a 2.43 ERA in 25 games for Washington.To make roster space for Zimmerman and Solis, the NL East-leading Nationals optioned outfielder Michael A. Taylor and right-hander Lucas Giolito to Triple-A Syracuse. ' ' '