A U.S. sprint car driver was killed during a crash in warm-up laps Friday night at Williams Grove Speedway, prompting officials at the track to call off Saturday's planned races.

James Campbell Jnr died when his car crashed in the third turn. Witnesses told area television station WHTM that the car burst into flames after striking the outer wall and a second car struck it and flipped over.

Novak Djokovic had to fight off an upset bid from qualifier Ernests Gulbis, defeating the Latvian 5-7, 7-6 (9/7), 6-1 on Friday to reach the semi-finals of the Montreal Masters.

But Rafael Nadal, like Djokovic a former champion at the event, was unable to escape an on-form Kei Nishikori as the fourth seed sent out the Spaniard 6-2, 6-4 thanks in part to six double-faults from Nadal.

The designer of Tokyo's 2020 Olympics logo said Friday he has withdrawn some designs created for drinks giant Suntory in the wake of fresh plagiarism allegations.

The move comes just over a week after under-fire designer Kenjiro Sano described claims that he stole the design for his Olympics emblem as "completely baseless".

World number one Serena Williams continued her dominance over Germany's Andrea Petkovic with a 6-3, 6-2 victory in the third round of the WTA Rogers Cup on Thursday.

Top seed Williams hammered 28 winners and blasted nine aces to beat the 16th seeded Petkovic for the fifth straight time.

One of the smallest clubs ever to play in France's top flight could be in for a rude awakening on Sunday when Corsican minnows Gazelec Ajaccio face Paris Saint-Germain at the Parc des Princes.

PSG began their quest for a fourth consecutive Ligue 1 title with a 1-0 victory at Lille last weekend, despite playing more than an hour with 10 men following Adrien Rabiot's sending-off.

Mauricio Pochettino admits he still has work to do as the Tottenham manager reshapes his squad ahead of Stoke's visit to White Hart Lane on Saturday.

Pochettino's side slumped to an underwhelming 1-0 defeat at Manchester United last weekend and the Argentine remains keen to add to his options before the end of the transfer window.

Premier League champions Chelsea travel to Manchester City, last season's runners-up, on Sunday with manager Jose Mourinho embroiled in a growing row over accusations he has sidelined team doctor Eva Carneiro.

British media reports claim Carneiro will no longer attend matches or training sessions after Mourinho reacted furiously to the sight of her and physiotherapist Jon Fearn running on to the pitch to treat Eden Hazard during the latter stages of last weekend's opening 2-2 draw at home to Swansea City, which temporarily reduced Chelsea to nine players.

Chelsea manager Jose Mourinho found himself at the eye of a storm on Thursday as criticism mounted over reports he has sidelined the Premier League champions' team doctor Eva Carneiro.

British media reports claim Carneiro will no longer attend Chelsea's matches or training sessions after Mourinho lambasted her and physiotherapist Jon Fearn for running onto the pitch to treat Eden Hazard during the latter stages of last weekend's 2-2 draw at home to Swansea City.

Top-ranked Novak Djokovic began his preparation for the U.S. Open by defeating Thomaz Bellucci 6-3, 7-6 (7/4) Tuesday, advancing to the third round of the ATP Montreal Masters.

But there was no luck with the weather for Andy Murray, with the British second seed forced off court at 4-4 against Spain's Tommy Robredo when rain struck less than an hour before midnight, postponing the finish of the contest until Wednesday.

World number one Serena Williams rallied to advance to the third round of the WTA Rogers Cup on Tuesday by defeating Italy's Flavia Pennetta 2-6, 6-3, 6-0.

It was the 725th career match triumph for Williams, who withdrew from last week's Stanford event with a right elbow injury but launched her U.S. Open hardcourt warm-up campaign successfully.