LONDON (AP) Fiji moved to the brink of clinching the sevens rugby world series title after beating closest challenger South Africa 21-17 in the London final on Sunday.

The Fijians can win a third world series in four years by reaching the final in Paris next weekend in the last round, or advancing further than South Africa if the defending series champion stumbles early.

Fiji overcame an immediate yellow card to Sevuloni Mocenacagi for a tackle in the air at the opening kickoff in the final at Twickenham. South Africa exploited the man advantage to send over Stedman Gans.

The Fijians’ reply was stalled by errors until a minute before halftime, when Paula Dranisinukula claimed a turnover and Josua Tuisova barged through the defense to level the score on 7.

Fiji led for the first time straight after the break as Dranisinukula finished off an Amenoni Nasilasila break.

Nasilasila converted again, but Justin Geduld was just short with his conversion attempt after Ruhan Nel brought South Africa within two.

Jasa Veremalua played give and take with Josua Vakurunabili for another converted try and 21-12 with less than three minutes to go.

South Africa’s comeback was stymied by terrific Fiji defense, and it couldn’t grab the quick score it needed until seconds were left and Zain Davids crossed. The South Africans skipped the conversion to quickly set up for kickoff, but couldn’t make it work.

The victory was Fiji’s fourth in a row and fifth overall in the series, out of nine rounds. Its first London Sevens title since 2012 extended its overall lead from four points to seven.

But it’s only a two-team race after New Zealand lost to South Africa 14-5 in the quarterfinals.

Fiji ran through Canada and invitation side Ireland to make the final, and Ireland got up to beat England for third, the biggest surprise of the weekend.