Wales coach Warren Gatland says the strength of their bench played a major role in the narrow 9-6 victory over Australia at the Millennium Stadium on Saturday.
Wales, who will meet Australia in their pool in Japan, ended a 13-game losing streak against the Wallabies in an error-strewn arm-wrestle.
The ability to bring in experience off the bench, such as fly-half Dan Biggar and wing Liam Williams, gave Wales the impetus they needed in the closing stages, according to Gatland.
"I said that was the strongest bench we've put out in my time in Wales," Gatland told reporters.
"I thought the bench was outstanding. [Flanker] Ellis Jenkins was outstanding. [Lock] Cory Hill and the two front-rowers came on and did well. Dan [Biggar] had to come out and kick a pressure kick."
Neither side created anything in the way of try-scoring opportunities as both defences stood firm. Unforced errors played a role too, as did the slow ball at the breakdown.
"The breakdown was tough for both teams. In the first half, we weren't dominant enough in the collisions," Gatland said.
"The boys dug deep. From a defensive point of view, that was probably the most comfortable we've been against Australia."
Wales' victory might have been more comfortable had full-back Leigh Halfpenny, usually so dependable from the kicking tee, not missed two simple penalty opportunities, one from directly in front of the posts.
"I never thought I'd see the day Leigh missed two easy kicks," Gatland said. "The pleasing aspect was that it didn't affect his game and he came out in the second half and performed really well."
Gatland also praised the decision to play Scotland last weekend, which culminated in a 21-10 victory, gave them momentum going into the clash with Australia.
"The game last week was important for us. We probably wouldn't have won today had it been first up.
"We've got good momentum at the moment. Seven wins in a row. It puts pressure on those taking the field. We're in a really good place and looking forward to the World Cup next year."
Next up for Wales is a meeting with Tonga on Saturday. Gatland suggested he might field a new team with a clash against South Africa to come the following weekend.
"That's down to the depth we've built," he said. "In the past, we've made lots of changes and the performance hasn't always been good. But we have depth now and I'm confident we'll put in a good performance."