Atletico Madrid coach Diego Simeone said Diego Costa could miss the Champions League quarterfinal against Barcelona on Tuesday.

Costa left Atletico's training at the Camp Nou on Monday with an apparent knock to his right leg, and Simeone told Spanish public broadcaster TVE after speaking to medical staff that "if he came out of training early, it looks difficult for him to play tomorrow."

Boxing teams from Russia and Ukraine put aside political tensions Monday to contest a World Series of Boxing quarterfinal in Moscow, with the hosts landing most of the blows in the ring.

The Russian Boxing Team took a 4-1 lead against the Ukraine Otamans ahead of the return meeting in Donetsk next weekend in a contest that received added attention following Russia's annexation of Crimea and escalated military buildup on the Ukrainian border.

Labor officials are suspending work on part of the World Cup stadium where a worker died this weekend, creating a major headache for Brazilian organizers trying to get the site ready for the tournament's opening match on June 12.

Fast Engenharia, the construction company in charge of the stadium's temporary seats, said in a statement that it received notification from Sao Paulo state's labor secretariat late Monday that seat installation must halt until additional safety measures are implemented.

Barcelona goalkeeper Victor Valdes is expected to be sidelined for seven months after surgery on his right knee on Monday.

The 32-year-old Valdes underwent surgery in Germany after tearing the anterior cruciate ligament during a 3-0 win over Celta Vigo on March 26.

The Brooklyn Nets have gone from disappointment to dominant, a team that was booed on its home floor and now rarely loses there.

And pretty soon, the Nets will also be a playoff team.

After a 24-year wait, the English league title could be on its way back to Liverpool.

A 4-0 win over Tottenham on Sunday saw Liverpool overtake Chelsea and become the new Premier League leader in a close fight for the title.

Novak Djokovic stretched like a rubber band to hit a backhand. He sprinted into the other corner and scooped out forehands as if he was wielding a shovel. He ran forward to slice a ball off his shoetops. And he flicked a difficult half-volley past a weary Rafael Nadal for a winner.

That was just on the last point.

Six past winners, three domestic league leaders and many of the world's best players take their places this week in one of the strongest quarterfinal lineups in the 22-year history of the Champions League.

There appears to be no weak link in the last eight, with Manchester United unlikely to be written off by quarterfinal opponent and reigning champion Bayern Munich despite a disappointing Premier League season in the post-Alex Ferguson era.

Mao Asada of Japan won the free skate on Saturday to capture her third world figure skating title.

Asada, who held a slim 1.42-point lead after the short program, under-rotated three jumps but finished with 216.69 points, 9.19 ahead Julia Lipnitskaia of Russia.

Former world champion Lewis Hamilton avoided crashes and shrugged off a torrential downpour to claim a British record-equaling 33rd pole position at a thrilling Malaysian Grand Prix qualifier on Saturday.

In a session which had nearly an hour's rain delay, and was twice suspended for crashes on the slippery Sepang circuit, the Mercedes driver came out on top ahead of surging world title-holder Sebastian Vettel.