Martyn Williams may have been the most outstanding player of the RBS 6 Nations, but the Welsh flanker insists he still has something to prove when he makes his Lions debut against Bay of Plenty on Saturday.

The reason? Williams, of Cardiff Blues, has been named at openside in a powerful - possibly first-choice - Lions back row that includes England veterans Richard Hill and Lawrence Dallaglio.

Neil Back, the third member of England's elite World Cup-winning loose-forward trio, is suspended and Lewis Moody has been rested after playing against Argentina so Williams knows Saturday will a huge opportunity to lay out his Test credentials.

"I've got some pretty big shoes to fill in terms of that England trio of Back, Dallaglio and Hill which is a world-class unit that have been there and done it, so it is a great privilege for me to play with Lawrence and Richard," Williams said.

"I'm really looking forward to it. They are both tremendous athletes and hopefully I'll learn a bit from them. It's a big task and I can't wait to play."

The Lions were outgunned at the breakdown against Argentina in the 25-25 draw at the Millennium Stadium last week and Williams knows he will be in for a fierce battle against Bay of Plenty in Rotorua.

They will be no pushovers. Bay of Plenty beat Auckland to claim the Ranfurly Shield and finished third in New Zealand's national provincial competition.

There is unlikely to be any repeat of the Lions' tour opener four years ago, when they racked up a century of points in Perth against Western Australia.

"These games will be totally different to the openers in Australia. There is a great tradition of rugby at the Bay of Plenty and we'll get the kind of test we need before going on to the bigger games," said Williams.

"New Zealanders are particularly strong around the breakdowns so that is a huge task for us and we've really targeted that area. Everyone in the team has to play and it is just one of the areas we have to improve on.

"We've got a big responsibility first game up and it's the first chance to stake our claim for the Test spots but collectively we need a big performance to start the tour.

"The back row is going to be a massively contested area and possibly the most contested Test spots in the side.