Wales have impressed commentators so far this tournament, and young players such as 19-year-old George North, 20-year-old Toby Faletau and 23-year-old captain Sam Warburton have received particular praise.
"Team morale is fantastic," Jones said. "It's a young squad. With the younger players, they're more fearless, and they go out there and back themselves, that's what our guys have done."
101-times-capped Jones, who is now second choice fly-half behind 24-year-old Rhys Priestland, also said that the attitude of Wales's younger players has inspired the squad's veterans.
"We've had so many good youngsters come through, put their hand up and the way they've been playing they've raised the bar. That really has had a good knock-on effect for the rest of the squad.
"It's certainly the most competitive squad I've been part of."
Wales face Ireland in the World Cup quarter-finals on Saturday, October 8.