With just two events still to play in this year's IRB Sevens World Series - at Twickenham and Murrayfield this weekend and next weekend - the race is on between two supreme sides for the title of 11th overall champion.

Never before have things been so close with the final European climax to play. Defending Series champions South Africa are out of the contest, building for next year and beyond, England are defending their London title but are yet to win a Cup this year, Fiji took the spoils in Wellington but have performed in fits and starts, as have Kenya, a redoubled Australia and Argentina. There is no doubting the two teams of the moment: Samoa and New Zealand.

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Gordon Tietjens' eight-time World Series champions lie just three points behind the Pacific Islanders, who have won the last three events in Las Vegas, Adelaide and Hong Kong and lead the rankings for the first time ever.

It is fitting that the theme at Twickenham this weekend will be superheroes, for these two sides' fortunes have been entwined like a caped crusader's and his nemisis' all season: indeed, were it not for the Samoans' consistent brilliance and bullishness, not only would the kiwis be leading the way in pursuit of a ninth World title, they would also be unbeaten this season.

Samoa the nemisis

"Are Samoa our bogey team? They're the only team that's beaten us this year," said NZ coach Gordon Tietjens. "I accept that and they have played well, there's no question.

"I also certainly believe, though, that in the last two games we were in positions to win and were punished by two yellow cards. In Adelaide Kurt Baker was carded and I thought we had done well enough to win it, and then in Hong Kong the same player was sin-binned having scored two tries and we conceded two.

"That's the nature of Sevens though. Samoa have taken their opportunities and they have been in my opinion consistently the form team of the Series."

Since the first two events in Dubai and George, both of which were won by New Zealand, the Samoans have been the outstanding side, and have possessed the killer players.

Kiwi captain DJ Forbes has forged ahead and battled his heart out but consistently his forward pack has come second best to Samoa's with Alafoti Fa'osiliva peerless this season alongside the relentless go-forward of Ofisa Treviranus and aerial prowess of hulk Simaeka Mikaele.

In the backs too the islanders have proved more than a match. So often in a class of his own at half back, Tomasi Cama has found the going tough again against veteran magician Uale Mai and outside him his captain this year Lolo Lui has pulled the strings like an enchanted puppet master at first receiver. Classy and assured, Lui's all-round game has often seen the Samoans home.

And when they have needed that extra something, a game-breaker or match-winner, time and again Mikaele Pesamino has proved that he is, when fit, the game's most remarkable finisher. Pace off the mark combined with incredible levels of speed endurance and an uncanny eye for an intercept have helped take Pesamino's individual tally to 47 tries already - 19 more than the next man, Kenya's Collins Injera - and coach Stephen Betham will be praying that he in particular can stay fit, especially as Tietjens welcomes back two key players himself in Lote Raikabula and Sherwin Stowers.

Tietjens: There is hope for us

"There is hope for us because we did do enough in those last two games to win," stressed Tietjens. "Somebody told me the other day that we've played Fiji 14 times in the past two seasons and they've only beaten us once. And we've lost five times to Samoa this year. So we are certainly striving for the challenge of taking them on in the next two tournaments, which are going to be very tough."

After 15 years in the game Tietjens also knows only too well not to rule out any of the other challengers, especially at England's home of rugby where each and every player seems to find another gear.

"I think South Africa are going to want to prove a point on the same stages where they closed out the World Series last year. England have put together a formidable side for their home tournament, Fiji will be strong and we'll be trying to pull those three points back on Samoa, while they'll also be doing everything they can, probably training the house down right now.

"I always remember as a player that I wanted to play on the big grounds in New Zealand because they meant something, the Eden Parks and the Athletic Parks, and now for the younger players they look at these international venues and especially Twickenham looking to build a monster crowd.

"It's going to be extremely tough but for the players to get the chance to play at Murrayfield and Twickenham is a huge deal. My players have also been training the house down to get there because they love playing at those huge stadia, both are exciting and historically mean a lot to the players who in the past have probably only seen matches played there on the television.

"Exciting times and a chance to win a World Series as part of team playing at some of the most magnificent sports venues in the world."