Following is a summary of current sports news briefs. Heat upset arena rejected as polling place

The Miami Heat expressed disappointment on social media that their home arena was rejected as a polling place site for November’s general election, while a number of other NBA cities have welcomed an identical plan. In a proposal that was galvanized by the Los Angeles Lakers’ LeBron James earlier this summer, the idea was to make NBA arenas mega polling locations in order to allow as many registered voters to cast a ballot as possible — and to do so with safe social distancing. Authentic holds off Tiz the Law to win Kentucky Derby

Authentic held off a late challenge by favorite Tiz the Law to win the Kentucky Derby on Saturday at Churchill Downs and give the Hall of Fame trainer Bob Baffert a sixth win in the annual Run for the Roses. Authentic, ridden by John Velazquez, set the early pace and managed to maintain his speed down the stretch in the 1-1/4 mile classic, which was held without spectators due to the COVID-19 crisis. Johnson leads by one stroke at halfway point in Atlanta

Dustin Johnson struggled off the tee but birdied his last hole to card a second round even par 70 and cling to a one-stroke lead at 13-under par halfway through the season-ending Tour Championship in Atlanta on Saturday. As top seed in the season-long points standings, Johnson started the tournament 10-under with a two-shot lead thanks to the staggered scoring system and was the overnight co-leader with Jon Rahm. MLB roundup: O’s end 19-game skid vs. Yanks in DH split

Rookie Ryan Mountcastle homered and drove in three runs, and the Baltimore Orioles defeated the visiting Yankees 6-3 in the second game of a doubleheader Friday night to end their 19-game, head-to-head losing streak against New York. The Yankees beat the Orioles 6-5 in nine innings in the first game of the twin bill, New York’s 18th straight victory in Baltimore. The Yankees’ last loss at Camden Yards before Friday’s nightcap came on July 10, 2018. Nuggets coach Malone hits out at NBA’s ‘criminal’ guest policy

Denver Nuggets head coach Michael Malone has criticized the National Basketball Association’s (NBA) policy that prevents the families of coaches entering the bubble-like campus near Orlando, where the season resumed amid the COVID-19 pandemic. The NBA, which was suspended in March due to the novel coronavirus outbreak, re-started in July at the Walt Disney World sports complex in Florida without fans and strict safety protocols in place. Bills CB White signs four-year $70 million extension

All-Pro cornerback Tre’Davious White agreed to a four-year, $70 million contract extension with the Buffalo Bills on Saturday, multiple outlets reported. The deal includes $55 million guaranteed and brings the total value of his contract to $82.1 million, according to ESPN’s Adam Schefter. Pospisil outlasts Bautista Agut to reach fourth round

Unseeded Canadian Vasek Pospisil pulled off another stunning upset at the U.S. Open when he knocked out Spain’s eighth seed Roberto Bautista Agut 7-5 2-6 4-6 6-3 6-2 in the third round on Saturday. Pospisil, who eliminated fellow Canadian and 25th seed Milos Raonic in the second round, has already spent nearly 10 hours on court in three matches at Flushing Meadows after this contest lasted three hours and 40 minutes. Mladenovic-Babos withdrawn from U.S. Open doubles after quarantine notice

Doubles top seeds Kristina Mladenovic and Timea Babos were withdrawn from the U.S. Open on Saturday, hours before they were due on court after Mladenovic received a COVID-19 quarantine notice from public health officials, the United States Tennis Association (USTA) said. Mladenovic is one of 10 players who came in contact with France’s Benoit Paire, who was pulled out from the men’s field at the hardcourt major after testing positive for the new coronavirus. Williams still learning to live with ‘Serena’ target

Winning a Grand Slam is hard. For Serena Williams, managing the overwhelming expectations that come with a two-decade long career in the spotlight seems even harder. The third seed advanced into the second week of the U.S. Open on Saturday, surviving a third-round scare from fellow American Sloane Stephens before winning 2-6 6-2 6-2 in her toughest test at this year’s tournament so far. Medvedev dismantles third-round opponent Wolf at U.S. Open

Russian Daniil Medvedev rolled through the U.S. Open third round by demolishing American J.J. Wolf 6-3 6-3 6-2 on Saturday. The third seed seized the early momentum, breaking Wolf’s serve for a 3-2 lead in the first set in which he committed just two unforced errors in a show of near-flawless play.