It was gold for Fiji, a bittersweet weekend for South Africa and heartbreak for Japan at the Tokyo Sevens on Sunday.

The Flying Fijians beat South Africa 33-26 in a sensational final thanks to a last-minute try from Waisea Nacuqu. It was a fitting end to a great weekend of rugby, with the lead changing hands a number of times, and sets the HSBC Seven World Series up nicely for its premier event in Hong Kong next weekend.

South Africa, despite the defeat, move top of the series standings with 116 points, with New Zealand, which finished fourth after losing 21-12 to England in a feisty third-place playoff, on 114.

Fiji's efforts sees it close the gap on the top two with the 22 points it won here giving it 95, while England has 85 with three rounds of the series left to play.

"Our coach told us to focus on ourselves and make our one-on-one tackles," said Fiji captain Osea Kolinisau. "He's also told us 1,000 times that communication is really important. When we get that right, we can do things perfectly and play to the game plan."

His coach Ben Ryan agreed, saying that when the Fijians get in their zone, there were very few sides that could live with them.

"It's pretty breathtaking to watch when they get it right," the Englishman said. "And there were times today when we did get it right."

While Ryan and his team were able to celebrate with the large number of Fijians in the crowd, Japan's weekend at the Prince Chichibu Memorial Rugby Ground ended in tears after it lost 24-19 in sudden death extra-time in the semifinal of the third-tier Bowl to Wales, which went on to beat Scotland 28-21 in the final.

In the other minor finals, Australia beat the United States 17-12 to win the second-tier Plate, while Argentina hammered Samoa 26-0 to claim the Shield for the bottom four sides.

Japan got off to the best possible start on Day 2 with its first win over a core team since 2006. And it was no ordinary victory as it hammered Samoa, series champions in 2009-10 and fourth the last two years.

Lote Tuqiri and Kenki Fukuoka grabbed a pair of tries each and there were further five-pointers for Masaki Watanabe and Lomano Lemeki with Kosuke Hashino banging over five conversions and Katsuyuki Sakai one as Japan won 42-12, its first victory over Samoa in 16 attempts.

"It was a good victory, an awesome victory," said Tuqiri. "It's good to be back scoring tries and I am very happy for the team."

But the good work was ruined a few hours later as Japan's inexperience of big-time sevens came back to haunt them.

Tomohiro Segawa's men led 14-0 against Wales thanks to tries by Lemeki and Hashino, who added two conversions.

But two moments of madness in the space of a minute allowed Wales to pull within two points.

Yoshikazu Fujita, who had an outstanding game against Samoa, threw a pass that was never on and resulted in an intercept try, before the whole team lost concentration and allowed the Welsh to take a quick restart that resulted in James Davies crossing for a soft and avoidable try.

Ross Jones then added a third five-pointer for Wales before Lemeki scored his second a minute after the hooter, giving Sakai a chance to win the game. Sadly for the home fans — and most if not all the neutrals in the stands — his conversion didn't have the legs and the teams went into extra-time.

Despite having a man in the sin bin, it was the Welsh who finished stronger, and Alex Webber's second try of the game ended the game and silenced the crowd.

"We created enough chances," rued Fujita. "But hopefully we can use this experience and be successful in Hong Kong."

Japan is one of 12 countries playing next weekend in the former British colony for one automatic spot on next year's circuit.