Moto GP star Valentino Rossi confirmed he will end his career with Yamaha but called on teammate Jorge Lorenzo to show him "respect" in what could be the Italian's 15th and final season.

Nine-time world champion Rossi missed out on the 2015 world title by five points to Lorenzo after the Spaniard won the final race of the season in Valencia in controversial fashion.

Novak Djokovic opened his Australian Open title defense with a straight-sets win, before going to the defense of his sport as reports of match-fixing overshadowed the first day of the season-opening Grand Slam.

Djokovic had a 6-3, 6-2, 6-4 win over Chung Hyeon of South Korea at Rod Laver Arena on Monday, immediately after women's defending champion and No. 1-ranked Serena Williams started her bid for a seventh Australian title with a 6-4, 7-5 win over No. 34-ranked Camila Giorgi.

Katie Ledecky was barely in the pool when American swim great Michael Phelps was asked about the precocious teenager who seems to mow down world records at will.

"It's always something special when she gets in the water," Phelps said with an eye toward the timing board.

San Antonio stretched its franchise-record unbeaten streak this season to 24-0 by routing Texan rival Dallas 112-83 on Sunday.

The result opened a 13-game gap between the top and second teams in the NBA's Southwest Division, and meant the Spurs were now only 1-1/2 games behind Golden State for the Western Conference and overall league lead.

Real Madrid's second straight five-goal performance under new coach Zinedine Zidane came at the high price of losing Gareth Bale and Karim Benzema to injury on Sunday, while Luis Suarez scored a hat trick to lead Barcelona's 6-0 demolition of 10-man Athletic Bilbao.

As the two powerhouses got goals from their trios of star strikers, Atletico Madrid quietly churned out a 3-0 win at Las Palmas to retain its provisional lead of the Spanish league.

Rafael Nadal admitted Saturday he faces a "very, very dangerous" Australian Open first-round clash against Fernando Verdasco with memories still fresh of their epic 2009 semi-final duel.

At five hours and 14 minutes, that battle seven years ago was then the longest match in the tournament's history with a shattered Nadal showing incredible resilience to win 6-7 (4/7), 6-4, 7-6 (7/2), 6-7 (1/7), 6-4.

Oklahoma City point guard Russell Westbrook looked like himself again on Friday, notching his fourth triple-double of the season to lead the Thunder to a 113-93 victory over the Minnesota Timberwolves.

Coming off a forgettable display against Dallas on Wednesday, in which Westbrook failed to score a point before he was ejected in the second quarter, Westbrook scored 12 points, 10 assists and 11 rebounds before sitting out the fourth quarter with the hosts in full control.

Maria Sharapova Saturday said she is in good shape and not worried about a lack of match practice going into the Australian Open after an injury-hit start to the year.

The fifth seed, attempting to win her first title at Melbourne Park since 2008, pulled out of the season-opening Brisbane International with a left forearm problem, but the upbeat 28-year-old said she's raring to go.

World number one Serena Williams confirmed Saturday she plans to play doubles at the Olympics in Rio this year and is even mulling the mixed event if she can find a partner.

Williams and sister Venus have an enviable record for the United States at the Olympics, claiming the women's doubles gold in 2000, 2008 and 2012.

Despite starkly contrasting playing philosophies, Liverpool manager Jurgen Klopp and his Manchester United counterpart Louis van Gaal are grappling with similar problems ahead of their meeting at Anfield on Sunday.

While Klopp espouses hard-running, high-pressing, "heavy metal" football, Van Gaal is all about patient ball retention, but both men are yet to find a consistent formula for scoring goals.