Pacific Nations Cup holders Japan saw their hopes of retaining the title extinguished Sunday as they crashed to Tonga 24-20 in Tokyo.
It was a bitter blow for the home side, who had gone down 25-19 to Fiji on Tuesday, and left them propping up the standings with only two points, a far cry from last year's victorious performance.
Samoa overcame Fiji 29-26 themselves on Sunday to lay a hand on the trophy with one round of matches to go, leading the table on eight points after two wins from two games.
They play Japan in Tokyo next Sunday and a win will give them the cup. But if the hosts secure a consolation victory, the tournament's last match between Fiji and Tonga -- both currently on five points -- will decide the title.
Japan's clash with Tonga was closely fought. Visiting fly-half Kurt Morath opened the scoring with a penalty in the eighth minute, but Japan soon started to get their high-paced rugby into gear.
Flanker Hendrik Tui was pushed over by the backs to score a try on his debut in the 13th minute, and Ayumu Goromaru converted for a 7-3 lead.
But an error from the restart handed Tonga the perfect attacking platform and winger Alaska Taufa scored, with Morath converting to put the visitors back in front.
Goromaru knocked over a penalty from 38 metres out to level the scores only for Tonga's scrum half Taniela Moa to cross the line minutes later, with Morath converting again to put his team 17-10 up at half time.
Two minutes into the second half a Goromaru penalty struck the post, but he seized the rebound, powered over for the try, and then made the conversion to tie the match at 17-17.
The two teams took turns to lay siege to their opponents' line and remained deadlocked until the Tongans worked an overlap down the left wing in the 61st minute, substitute Paula Kaho crossed over and Morath converted.
Goromaru's second penalty in the 69th minute narrowed the gap, but the Brave Blossoms were unable to take advantage when Tonga's substitute centre Mafileo Kefu was sin-binned.
"We made some elementary errors at crucial times in the game," said Japan coach Eddie Jones. "We gave them some ridiculously easy points and created enough opportunities to win the game."
Samoa -- who won the 2010 edition of the tournament and had beaten Tonga 20-18 on Tuesday -- prevailed by a single penalty over Fiji.
Fly-halves Ki Anufe and Setareki Koroilagilagi shared a penalty each in the first five minutes before Fijian scrum-half Nemia Kenatale touched down in the 10th minute and Koroilagilagi converted for a 10-3 lead.
A converted Ben Masoe try for Samoa and two more shared penalties made it 13-13 after 27 minutes.
Two unconverted tries by Samoan winger David Lemi either side of half time gave his team a 10-point lead, but after a Netani Talei try for Fiji and two more penalties, Samoa's advantage was down to five points with seven minutes left, 26-21.
Anufe knocked over his fourth penalty to steady Samoan nerves, and although Fiji substitute Talemaitoga Tuapati pulled off one more try, there was only one minute left on the clock.
"Both teams gave it their all today," said Samoa coach Stephen Betham. "The last few minutes were very competitive as Fiji never gave up, so I am very proud of my players."