Taylor Fritz has credited the quality of his serve as one the main reasons he made a winning start at the ATP Finals after a 6-3, 6-4 victory against Lorenzo Musetti.
Italy's Jannik Sinner launched his bid to retain the ATP Finals crown with a convincing 7-5, 6-1 victory over Canada's injury-hit Felix Auger-Aliassime.
Carlos Alcaraz and Alexander Zverev both claimed opening-day wins in ATP Finals action on Sunday in Turin.
Jannik Sinner defeated Felix Auger-Aliassime 6-4, 7-6(4) in the Paris Masters final on Sunday, notching up his fifth Masters 1000 title and his fifth title of 2025.
Cameron Norrie rallied from a set down to produce one of the biggest upsets at the ongoing Paris Masters when he defeated world number one Carlos Alcaraz.
Grigor Dimitrov made an impressive return from injury after claiming a 7-6(5), 6-1 victory against world No 56 Giovanni Mpetshi Perricard in the first round of the Paris Masters.