Wales are now unofficially ranked the number one side in the world after Australia defeated New Zealand in the Rugby Championship.
The All Blacks have provisionally slipped off the top spot for the first time in 10 years following their 47-26 defeat in Perth.
Wales will officially be ranked top on Monday if they avoid defeat against England on Sunday at Twickenham.
The Wallabies also await Wales in the pool stage in Japan.
Warren Gatland's side are currently boast a 14-match winning sequence, including a rare win against Australia in November, 2019.
This includes a third Grand Slam since the New Zealander took charge of Wales ahead of the 2008 Six Nations.
The last of those triumphs came as Wales won the 2019 with victory over Ireland in Cardiff in March.
Wales officially being ranked number one in the world would be the first time since the system was introduced in 2003.
South Africa were the last side to be ranked above the All Blacks as number one in the world, in November 2009, with New Zealand since winning the 2011 and 2015 World Cups.
It could be an afternoon of records at Twickenham with captain Alun Wyn Jones setting a Welsh record 135th Test appearance when he captains the team in Sunday's World Cup warm-up against England.
The 33-year-old will make his 126th appearance for Wales, having also won nine British and Irish Lions caps.
He beats the mark set by prop Gethin Jenkins, who made 129 appearances for Wales and played in five Lions Tests.
"It's not really a focus for me but it's validation for the support network I've had throughout my career," said Jones.
"Not just in the professional realms, but my family, my wife and my children too. That makes me proud, but a of people have contributed to my career from intermediate level, domestic level and international level.
"There are a lot more people for me to thank. That is more special for me than the number itself."