Watson played for the British & Irish Lions in South Africa two years ago but struggled with injury last season, hopes to make up for previous World Cup disappointment.
In 2015 he was cut from the final selection and four years' later in Japan suffered a knee injury in Scotland’s first game and played no further part in the tournament.
“I have only played one game in a World Cup so I am obviously massively motivated to try and get to another and hopefully play a few games in it,” he told a virtual press conference.
“But then so is everyone else. Some people are going for their first World Cup, some are going for their third, so everyone is just as motivated.”
Watson is a favourite for the squad but with the emergence of Rory Darge and the arrival of former Australia international Jack Dempsey in the Scotland squad nothing is sure.
“I think if you don't back yourself you're doing the wrong job. But there's an amazing group of players in the back row and I think it's probably one of the most hotly contested positions for the plane. So it's going to be tough, boys have come in and have made the group even more competitive."
Watson is expected to get a run out this Saturday as Scotland continues their preparations with a second pre-World Cup warm-up test, this time against hosts France at Murrayfield.
They beat Italy 25-13 at Murrayfield last Saturday but Watson did not play in a largely experimental selection.
“When you go into these games before a World Cup you know you might only get one game to show what you can do. But I think for everyone, it's just sort of not looking too far ahead at the moment and getting on the plane to France and then go from there,” he added.
