London - Wales star Sam Warburton has compared arch-rivals England to world champions New Zealand ahead of their Six Nations clash in Cardiff on Saturday.
Grand Slam champions England will arrive in the Welsh capital aiming for a 16th successive Test match win against all opponents.
The All Blacks hold the world record of 18 straight international wins by a tier-one nation but another Six Nations clean sweep this season would see England go one better.
"England are deservedly tagged as the best team in the northern hemisphere," Warburton told the BBC.
"It's a fair judgment to compare them to the All Blacks right now -- that's how good they are. It is going to take a huge game out of us to get a win and it will be one of the biggest games of the championship for sure."
Even when they are not one of the world's leading teams, England, for historical reasons, remain the one their European rivals want to beat above all others.
But they have become an even bigger target under Eddie Jones, with the Australian yet to lose a match as England boss after taking over after a 2015 World Cup where defeat by Wales prevented England getting out of the group stage and played a major role in the sacking of Stuart Lancaster.
"If you're Wales the biggest game you play in the Six Nations is England," said back-row forward and former skipper Warburton.
"If you're Scotland, it's England. If you're Ireland, it's England. Or if you're France or Italy, it's England," added Warburton, whose father was born in England.
"We know as players that's the one game the fans look forward to most and you sense that in the build-up. It's a huge occasion for everyone in Wales."
England, who beat Wales twice in 2016, started the defence of their Six Nations title with an unconvincing 19-16 win against France at Twickenham on Saturday.
By contrast, Wales launched their Six Nations with a 33-7 win away to Italy the following day that included 30 unanswered points in the second half in Rome.
Warburton, back in the ranks this season after experienced lock Alun Wyn Jones was appointed captain by interim coach Rob Howley, could miss out on a starting berth against England if No 8 Taulupe Faletau recovers in time from a knee injury.
Ross Moriarty was at No 8 against Italy in a back-row featuring Warburton and Justin Tipuric.
"The back-row competition is so fierce at the minute, I don't want to put pressure on him, but Toby (Faletau), when he's playing well, is one of the best players in the world," said Warburton.
"If he did come back I'm sure there would be a few selection headaches in the back-row because Ross and Justin went extremely well against Italy."
England and Wales will name their teams on Thursday.