(Photo credit: Robert Deutsch-Imagn Images)

If there were any nerves in opening his title defense of the Nitto ATP Finals, Italy's Jannik Sinner brushed past them with ease on Monday.

Sinner won his 27th consecutive indoor match with a 7-5, 6-1 victory over Canadian Felix Auger-Aliassime in the Bjorn Borg Group before a partisan crowd at the Inalpi Arena in Turin, Italy.

Sinner never faced a break point in the one-hour, 41-minute triumph over a hobbled but game opponent. He won 88.9% (32 of 36) of his first serve points and 62.5% of the hard-serving Auger-Aliassime's second serves.

Auger-Aliassime fended off two break points in the sixth game and a set point in the 10th to even the first set at 5-5. But after a love hold by Sinner, the fast-rising Canadian faltered on the fifth break point of the set, which ostensibly ended his chances for victory.

Sinner captured the second set in 40 minutes, breaking in the second and sixth games of the set.

Auger-Aliassime took medical timeouts after the first set and during two breaks in the second set, indicating pain in his calf.

'It was a very tough match until 6-5,' Sinner said. 'I had some chances to break. He served very well, only once I missed a return, but it can happen. He played some very aggressive tennis, so I'm happy to overcome a very tough test today. Obviously winning the first match is very important in this competition and this format. I'm very happy.'

Sinner admitted that playing an injured opponent can be tricky.

'You still have to be very consistent, with a great balance on the court,' Sinner said when asked about facing a physically struggling opponent. 'Especially mentally, it is a bit different, but at the same time it is an advantage. You have to say that. You have to use it in the right way, even if you don't want it to be like this.'

Sinner will take on Germany's Alexander Zverev in the second of three round robin matches on Wednesday.

The nightcap did not go as well for the Italian fans.

Like Sinner, Taylor Fritz had the health advantage over native son Lorenzo Musetti and cruised to a 6-3, 6-4 victory in the Jimmy Connors Group.

Musetti is making his ATP Finals debut and did it in 'lucky loser' fashion. He fell to Novak Djokovic in the finals of the Hellenic Championships in Athens on Saturday, but the Serbian withdrew from Turin, ceding his spot to ninth-ranked Musetti.

Fritz was a model of consistency throughout the match. He served up 13 aces with no double faults, won 10 of 14 net points and amassed 34 winners.

'I am really happy. I thought I did a lot of things really well,' Fritz said. 'I did a great job early on in the match to serve my way out of trouble and save some break points. The whole second set I played well and had a lot of chances to break that I didn't get. I am really happy I was able to serve it out there and it didn't come back to ruin it.'

The California native did have to fight off four break points in the third game of the match, but drew energy from that and broke Musetti in the next game. The Italian only won three more points on Fritz's serve in the set.

Fritz also broke early in the second set, battling back from 40-15 down. He won 16 straight points on his serve in spoiling Musetti's debut in Turin.

Fritz is hoping to win one more match than he did last year, when he fell to Sinner in the finals.

'Every time I come here, I like the conditions and it is very easy to get motivated,' he said. 'You can lock in, it is the last tournament of the year and it is the ATP Finals, it is a big deal.'

He has a big challenge on his hands on Tuesday, facing Spain's Carlos Alcaraz, who has an extra day of rest after defeating Alex de Minaur in straight sets on Sunday.

--Field Level Media