Wales coach Warren Gatland marked Hallam Amos's 21st birthday Thursday by calling him up for crunch Rugby World Cup Pool A clash with England on Saturday.

Amos replaces the experienced Alex Cuthbert, who drops to the replacements bench at Twickenham after a series of disappointing performances.

Gatland has had to patch together a starting XV after losing several key players to injuries over the past few weeks.

But there is no place for experienced scrum-half Mike Phillips who had been called up when first choice Rhys Webb was ruled out of the tournament before it got under way.

Instead Gatland has entrusted the pivotal scrum-half position to Gareth Davies, who will make only his second start for Wales.

Outside him fly-half Dan Biggar will fill the kicking role star fullback Leigh Halfpenny would have had before he, like Webb, suffered a serious injury in the final warm-up Test against Italy.

Elsewhere, 115 times-capped prop Gethin Jenkins will start his fourth World Cup campaign, packing down in the front row alongside Tomas Francis and hooker Scott Baldwin.

Sam Warburton captains the side and takes his place in a back row that also features Dan Lydiate and Taulupe Faletau. The impressive Justin Tipuric failed to dislodge any of them but is on the bench.  

Gatland, who guided Wales to the semi-finals in 2011 where they lost narrowly to France despite being reduced to 14 men for an hour after Warburton was sent off, said the team would have to play substantially better than in the facile win over Uruguay.

"Both sides kicked their tournament off with a bonus-point win (England beat Fiji), but we know we will need to step up at Twickenham on Saturday," said Gatland.  

Whoever loses will struggle to reach the quarter-finals from the Pool of Death. England and Wales still have to play Australia.

Team (15-1)

Liam Williams; George North, Scott Williams, Jamie Roberts, Hallam Amos; Dan Biggar, Gareth Davies; Taulupe Faletau, Sam Warburton (capt), Dan Lydiate; Alun Wyn Jones, Bradley Davies; Tomas Francis, Scott Baldwin, Gethin Jenkins

Replacements: Ken Owens, Aaron Jarvis, Samson Lee, Luke Charteris, Justin Tipuric, Lloyd Williams, Rhys Priestland, Alex Cuthbert.

Coach: Warren Gatland (NZL)
Source: AFP