Novak Djokovic has made the ideal start in his quest to win a record-equalling sixth ATP Finals title.
The world number two easily beat Italy's Matteo Berrettini in straight sets at the O2 Arena in London.
However, things weren't as rosy for Roger Federer, who was beaten by Dominic Thiem in his tournament opener.
It's the second year in a row that the seven-time Dubai Duty Free Tennis Championships winner has lost his opening match at the ATP Finals.
Raphinha, Fermin score as Barcelona beat Athletic in home opener
Raphinha and Fermin Lopez scored as Barcelona beat Athletic Bilbao 2-0 at the Camp Nou on Thursday in their first home match of the LaLiga season.
Chelsea and Fulham reach League Cup third round as Welbeck scores on debut
Chelsea has eased into the League Cup third round with a 2-0 victory over third-tier Luton Town on Thursday as Danny Welbeck marked his debut with a goal in Xabi Alonso's first competitive home match in charge.
PSG to meet Barca, Man City as Champions League draw throws up marquee ties
Champions League holders Paris St Germain will take on Barcelona and Manchester City in this season's league phase, while record 15-time champions Real Madrid will face Inter Milan and Arsenal after Thursday's draw in Monaco set up several mouth-watering clashes.
Abbas gives Pakistan slight edge as England battle back at Lord's
Pakistan bowler Mohammad Abbas took four wickets as his side just edged the first day of the second test against England at Lord's on Thursday although the hosts clambered back from a rocky start to end a weather-shortened day on 248-9.
UEFA suspends FIFA boycott threat but steps up pressure on world body
UEFA said on Thursday it had provisionally suspended plans to withdraw European teams from FIFA competitions after world football's governing body confirmed its controversial FIFA Forward Enterprise project had been permanently abandoned.
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