The South Sea Islanders started last night's match in 10th place in the rankings but their win over the No.6-ranked grand slam champions allowed them to leapfrog the Scots, who defeated them in Apia in June. The result in Cardiff means that failure to beat the Springboks today will leave Scotland with no chance of making the top-eight seeds for the next World Cup.
If that is a pitiable position to be in, the last night Wales were just pitiful. Humiliation awaits when they take on New Zealand in their next Test unless they can summon a monumental recovery. This loss followed another home defeat against Argentina.
The Six Nations winners seemed helpless as Samoa scored tries through full-back Fa'atoina Autagavaia, centre George Pisi and substitute Jonny Leota, while Pisi's brother Tisi kicked 11 points in a game when the lead changed hands six times. Leigh Halfpenny scored four penalties for the hosts as well as converting Ashley Beck's 80-metre interception try, but Wales have now suffered five successive defeats and appear hapless in so many areas.
"I'm not really sure where to start," said Ryan Jones, the Wales captain. "We came second best in quite a few facets of that game. It slowly slipped away from us and we didn't have enough in the end. Similar faults to last week – we played rugby in the wrong areas."
Their demise is alarming, and although head coach Warren Gatland will return to mastermind next week's preparations having been away on British and Irish Lions business, Wales seemingly have little hope of troubling either the All Blacks or Australia, who they face a week later.
That should not take away from what was a spectacular display from Samoa, though. A closed roof ensured perfect allowed the pitch to be protected from persistent drizzle in the Welsh capital, but Wales were engulfed by a Samoan onslaught.
Taiasina Tuifu'a raced clear on halfway after catching the Welsh defence napping, and then it was a case of a simple passing movement that ended with Autagavaia touching down. That had taken just 64 seconds.
Halfpenny replied with two penalties before Wales scored an opportunist try through Beck. Halfpenny's conversion, put Wales 13-7, but any joy was short-lived when Pisi scored a penalty of his own.
Kahn Fotuali'i put Samoa in the lead and they were in charge despite a revival led by Halfpenny, who put Wales 19-18 ahead. Another Pisi penalty and Leota's late effort sank Welsh hopes.
Wales captain Ryan Jones was at a loss to explain his side's 26-19 defeat to Samoa in Cardiff tonight.
Jones captained Wales for a record 29th time as Rob Howley's side looked to get their autumn campaign back on track following the loss to Argentina.
But the home team were outplayed by Samoa throughout and Jones said: "I'm not really sure where to start.
"We came second best in quite a few facets of that game. It slowly slipped away from us and we didn't have enough in the end. Similar faults to last week - we played rugby in the wrong areas."
"When you come off the back of some disappointing results things tend to snowball, but we have to draw a line under that.
"As players we have to take it on the chin because we have two of the best teams in the world coming next [New Zealand and Australia].
"There is no hiding place. We have front up and make sure we turn up in a week's time.
"What could have been one of the greatest days in my career has turned into one of the lowest."