Warren Gatland is targeting a first autumn series clean sweep for Wales following their 9-6 win over Australia on Saturday.
Victory over the Wallabies for the first time since 2008 has boosted confidence in the camp, with Tonga and South Africa now standing between Wales and a perfect autumn record.
They managed three successes from four attempts in 2002 and 2016 before New Zealand and Australia, respectively, ended their winning runs.
But victory over Australia has seen Wales claim seven wins on the bounce - their longest unbeaten run since Warren Gatland's reign as head coach began 10 years ago - to improve the mood in the camp.
"We have had a good run against South Africa in recent years, so it would be nice if we could win that one," he said.
"We will have got a lot of confidence [from beating Australia]. We will make changes for Tonga next week, and the group that played against Australia will work hard on a conditioning week.
"It is always nice to get that win against a southern hemisphere team, so there is a bit of pressure on the guys who will take the field against Tonga."
Wales' win over the Wallabies came before they meet again in a World Cup pool match next September.
"We definitely will get better as a team over the next six to 12 months," Gatland added.
"The players really do believe they can have a good autumn, hopefully a successful Six Nations and then start to think about doing well in the World Cup.
"The players will know they are good enough to beat Australia, and good enough to beat Australia when they have just come off a Rugby Championship.
"We spoke in the changing room after the game about how much we think we can improve in the next 12 months.
"We have said in the past that the more time we have together, the better we get. Having that game against Scotland last weekend was good for us and definitely improved our performance for Australia.
"There is some real momentum at the moment, and that is now seven wins in a row.
"There is a lot at stake in the next 10 months in terms of Six Nations and World Cup places. We feel we are in a really good place as a group and really looking forward to the next year."