NEW YORK -- When the U.S. Open decided to give 2009 champion Juan Martin del Potro a wild-card invitation this year, it rankled American player Steve Johnson.What if, Johnson wondered aloud, del Potro was to wind up beating someone from the United States in the first round of the countrys Grand Slam tournament?That didnt come to pass: del Potro faced a fellow Argentine in his opening match at Flushing Meadows. As it happens, though, del Potros opponent in the second round in Arthur Ashe Stadium on Thursday night will be -- yes, you guessed it -- Johnson himself.As it is, Johnson barely made it to this intriguing matchup.In the first round on Tuesday, the 19th-seeded Johnson, who won two NCAA singles titles at Southern California, dropped the opening two sets and needed to save six match points before coming all the way back to beat Evgeny Donskoy 4-6, 1-6, 7-6 (2), 6-3, 6-3. Johnson saved four match points while trailing 5-2 in the third set, then two more while down 6-5 in that set.Afterward, Johnson acknowledged that he came out tight in that match because he felt the pressure of being an American playing in the U.S. Open.I shouldnt let the moment get the best of me, he said, and it did for a bit.Del Potro had a much easier time in his opening match, beating countryman Diego Schwartzman 6-4, 6-4, 7-6 (3).A little more than two weeks ago, fresh off earning a silver medal at the Rio de Janeiro Olympics, del Potro was awarded his wild card, allowing him into the main draw of the U.S. Open for the first time since 2013. He missed 2 1/2 years worth of major tournaments because of three operations on his left wrist, only returning to Grand Slam action at Wimbledon in June.Once ranked as high as No. 4, he is currently at No. 142 because of so much time away from the tour, and he wasnt high enough to gain direct entry into the field at Flushing Meadows.The worst part of my life is totally in the past, del Potro said, and Im living a good present and looking forward for a good future.Here is what else to watch on Day 4 of the U.S. Open:WILLIAMS SISTERS: Both Williams sisters will be in action, in consecutive matches on Ashe. First, No. 6-seeded Venus Williams will take on Julia Goerges of Germany in the last day session match in the main stadium. Then No. 1 Serena Williams will face Vania King in an all-American matchup to start the night session. The siblings are coming off quite contrasting first-round outings on Tuesday. Venus labored during a three-set victory. Serena, who came to the U.S. Open with questions about a sore right shoulder, looked perfectly fine during her straight-set win, pounding serves at up to 121 mph, including 12 aces. Serena is bidding for a 23rd Grand Slam singles title -- that would break a tie with Steffi Graf for the most in the Open era, which dates to 1968.MURRAY: Three-time major champion and two-time Olympic singles gold medalist Andy Murray faces Marcel Granollers in the afternoon. Theyve played seven previous times, with Murray winning six. Murray, who won his first Grand Slam title at the U.S. Open in 2012, can become only the fourth man in the Open era to reach the final of each major tournament in a season, joining Novak Djokovic, Roger Federer and Rod Laver. Murray lost to Djokovic at the Australian Open in January, and the French Open in June, then won Wimbledon in July.FORECAST: There is rain predicted for Thursday, which used to create major scheduling headaches at the U.S. Open, but shouldnt be as much of a problem now. Thats because the tournament finally has a retractable roof atop Ashe -- and the $150 million structure passed its first test, used during a match for the first time Wednesday night as Rafael Nadal beat Andreas Seppi.---Follow Howard Fendrich on Twitter at http://twitter.com/HowardFendrichKent Bazemore Jersey . - The Washington Redskins have cut defensive lineman Adam Carriker and punter Sav Rocca. Anfernee Simons Blazers Jersey . 31, the CFL club announced Monday. The team also has yet to decide on the future of Doug Berry, who began the season as a consultant to the head coach but took over the offensive co-ordinators duties in July. https://www.blazerslockerroom.com/Brandon-Roy-City-Edition-Jersey/ . 4 Villanova with a 96-68 drubbing on Monday. Wragge hit 9-of-14 from behind the arc, matching Kyle Korvers school record for 3-pointers in a game set in 2003, as Creighton (16-3, 6-1 Big East broke a conference record with 21 treys in the rout. Anfernee Simons Jersey . The Barrie Colts defenceman, who impressed many with his play for Canada at the World Junior Hockey Championship, is the top-ranked skater in the February rankings. He has 19 goals and 24 assists for 43 points in 45 games with the Colts this season. Jusuf Nurkic Blazers Jersey . The judges scored it 48-47, 48-47, 49-46 for Jones (19-1). It was the champions closest call. Despite the loss, it was a remarkable show by the confident Swedish challenger, who had the best of the early rounds and then hung on in the fourth and fifth. ALLEN PARK, Mich. -- Detroit Lions coach Jim Caldwell says quarterback Matthew Staffords finger injury should not prevent him from playing this weekend against the New York Giants.The middle finger on Staffords right hand was taped up and covered by a white glove Sunday, when he threw for 223 yards in a 20-17 win over Chicago. Stafford had an interception returned for a touchdown in the fourth quarter.Caldwell said Monday the injjury affected Stafford against the Bears, but he should be able to practice.ddddddddddddDetroit (9-4) leads the NFC North by two games, and the Giants (9-4) would be the conferences top wild card if the season ended now.---For more NFL coverage: http://www.pro32.ap.org and http://www.twitter.com/AP-NFL. ' ' '