England, the champions for last two years, crashed out of the Dubai Sevens on the opening day after a shock loss to Portugal in their third and final Pool C match on Friday.
Fiji, who defeated New Zealand in the final of the opening leg of IRB Sevens Series in Australia, won all their matches in Pool A to advance to quarter-finals along with Kenya.
New Zealand were the other unbeaten team of the opening night -- winning all three of their matches in Pool B.
But it was Pool C which was the centre of attention as all four teams had four points going in to the last round of matches.
In their last pool match, Portugal authored the biggest upset when a late Pedro Leal penalty helped his side beat the fancied England 22-21 and reach the quarter-finals.
“I am very happy, very proud of the boys. We had a terrible game in Australia, we came here with young guys and we made it so we are very pleased,” said Leal.
“Two years ago we beat England too, but we didn't make the Cup quarters, here we have so we are very very happy.”
England had lost their opening match to South Africa 19-10, but remained in contention with a thrilling 19-17 win over Samoa.
Samoa had to depend on their superstar Lio Lolo for a hat-trick of tries to beat Portugal 24-19, but the European side showed they meant business when they upset South Africa 12-10 with a late try through their Aderito Esteves.
In the final round of matches Portugal beat England and Samoa knocked out South Africa winning their last match 10-5.
In the quarter-finals on Saturday, Fiji take on France, while Samoa will be up against Wales.
Canada, who topped Pool D with eight points from their three matches, will take on Kenya, while New Zealand will be up against Portugal.
Kenya went through from Pool A with a 12-5 victory over Scotland and a 10-7 win against Spain. Fiji beat Spain 14-0, Scotland 22-14 and Kenya 14-10.
New Zealand scored a 14-7 victory over Wales, 31-14 win over Russia and 17-7 win over Argentina in Pool B.
Canada topped Pool D with a 20-0 win over France, 28-28 draw with Australia and a 26-7 win over the USA.