NEW YORK -- Novak Djokovic double-faulted, then shook his right arm and grimaced.Seconds later, a weak serve produced a wince from the US Opens defending champion, then was followed by a missed forehand that gave away a set -- the first set dropped by Djokovic in the first round of any Grand Slam tournament since 2010.While he managed to emerge with a 6-3, 5-7, 6-2, 6-1 victory Monday night over Jerzy Janowicz of Poland, there were plenty of signs of trouble, starting with a visit from a trainer who massaged Djokovics bothersome arm after only five games.Asked about his health during an on-court interview, Djokovic deflected the question, saying, I dont think its necessary to talk about this now. Im through. Im taking it day by day.When the subject arose at his news conference, Djokovic again avoided addressing the topic, saying the trainers visit was just prevention; its all good.During the match, Djokovic hit first serves around 100 mph, sometimes slower -- 25 mph or so below whats normal for him. He hit second serves in the low 80s. He flexed that right arm, the one he has used to wield a racket on the way to 12 Grand Slam titles, and appeared generally unhappy, covering his head with a white towel at changeovers.Djokovics coach, Boris Becker, gnawed on his fingernails, looking as nervous as can be.All in all, Djokovics issues figure to loom large as the tournament progresses and were the most noteworthy development on a Day 1 at Flushing Meadows that did include drama elsewhere.There was 20th-seeded John Isners comeback from two sets down to edge 18-year-old Frances Tiafoe before a rowdy, standing-room-only crowd at the new Grandstand. And 26th-seeded Jack Socks five-set victory over 18-year-old Taylor Fritz in another all-American matchup.In other earlier matches, 2014 US Open champion Marin Cilic beat 108th-ranked Rogerio Dutra Silva 6-4, 7-5, 6-1, despite posting more unforced errors than winners (24-23). Britains Kyle Edmund, in his US Open debut, upset 13th-seeded Richard Gasquet 6-2, 6-2, 6-3.This was the No. 1-ranked Djokovics first match at a major since losing to Sam Querrey in the third round of Wimbledon, which ended the Serbs bid for a calendar-year Grand Slam after titles at the Australian Open and French Open. He exited the Rio Olympics in the first round this month, then sat out the Cincinnati Masters because of a sore left wrist.After all Ive been through in the last couple of weeks, its pleasing, of course, to finish the match and win it, said Djokovic, who lost to his next opponent, Jiri Vesely, at Monte Carlo in April. Look, each day presents us some kind of challenges that we need to overcome, accept and overcome.The left wrist appeared to be just fine against Janowicz, a former top-20 player who reached the semifinals at Wimbledon in 2013 and is now ranked 247th after his own series of injuries.Earlier in Arthur Ashe Stadium, Rafael Nadal stood near the net after winning his first Grand Slam match in three months -- 6-1, 6-4, 6-2 against Denis Istomin -- and unraveled the thick wrap of white tape protecting his all-important left wrist. He said hes still not back to hitting his forehand the way he does when hes at his best.Nadals afternoon match was played with the new $150 million retractable roof open under a blue sky, while offering some extra shade on a day when the temperature reached 90 degrees.The good news, Nadal said afterward, is that the pain is gone from his wrist, which whips those violent, topspin-heavy forehands that are the key to his success -- 14 of his 21 winners came off that wing.The bad news for Nadal?He still is working on feeling comfortable hitting down-the-line forehands, after sitting out -- not just zero real matches, but barely any practice, either -- from his withdrawal at the French Open in late May to the Olympics.Not easy to go 2? months out of competition, in the middle of the season, without hitting a forehand, Nadal said. I need to have the confidence again with my wrist.Both Nadal and his coach, his uncle Toni Nadal, described the way Rafael changed the way he hits a forehand during the Rio Games to try to avoid pain.Both said things are improving.But as Toni noted: We need a little time.Istomin, ranked 107th, was not likely to give Nadal much of a test. So what did he think of Nadals play Monday?For the first set, I was feeling that he was not hitting hard, Istomin said. A lot of short balls.Nadals summation of his day: Not very good, not very bad.The Associated Press contributed to this report. Venta Zapatillas Puma Baratas .com) - The Pittsburgh Penguins placed forward James Neal on injured reserve Tuesday. Puma Rihanna Baratas . Detroit and Boston are deadlocked, 1-1, and Tigers manager Jim Leyland could be forgiven if he was caught rationalizing instead of dissecting how his club could blow a 5-1 lead late in Game 2. http://www.pumabaratas.es/ . One game after a miserable showing in Oklahoma City, Gay tied a career high with 41 points and the Sacramento Kings cruised to a 114-97 victory at the New Orleans Pelicans on Tuesday night. Zapatillas Puma Baratas Online . Malkin got tangled up with Detroits Luke Glendening early in the third period and his left skate took the brunt of collision with the boards behind Pittsburghs net. Comprar Zapatillas Puma Baratas . Supported by three-run homers from Jayson Werth and Wilson Ramos, the young right-hander went seven strong innings in the Washington Nationals 8-4 victory over the Arizona Diamondbacks on Friday night. Each week during the 2016 college football season Ill offer up my selections and scores for the weekends biggest games, along with a handful of other key matchups to keep an eye on.Last year my selections went 104-33 (76 percent) when picking the straight-up winners during the regular season and 74-61-2 (55 percent) against the spread. The past two weeks have been rough here with my Insider picks and have dropped the straight-up record to 44-26 (63 percent) and the ATS record to just 26-41-2 (39 percent). On the Friday ESPN podcast, the record this past week was 2-2 and now stands at 14-13-1.Here are this weeks selections.Note: Lines from Westgate SuperBook as of Wednesdday morning.dddddddddddd (+) indicates a pick in which Phil Steele is taking an underdog with the points.No. 18 Tennessee Volunteers (-13.5) at South Carolina GamecocksSaturday, 7:15 p.m. ET, ESPN2The Volunteers went through the gauntlet of Florida, Georgia, Texas A&M and Alabama and got extremely banged-up, losing their past two games. Fortunately theyre coming off a bye and, while not anywhere near full health, they do get some players back, like linebacker?Darrin Kirkland Jr.?and?three offensive linemen who missed most of the Alabama game. ' ' '