LYON, France (Reuters) -Portugal coach Patrice Lagisquet has made four changes to his pack for the Pool C match against Australia in Saint Etienne on Sunday, suggesting some of his forwards need a break with fatigue an issue after two high-octane performances so far.
Portugal number eight Thibault de Freitas and blindside flanker David Wallis come into the back row after starting on the bench in the 18-18 draw against Georgia last time out.
Martim Belo returns to the second row in place of Jose Madeira and David Costa makes his first start of the tournament at loosehead prop.
"Some players were tired," Lagisquet told reporters on Friday. "It's difficult to play three games in a row at that level. We are not used to that and we need to refresh."
Nuno Sousa Guedes retains his place at fullback despite missing a late penalty against Georgia which would have given Portugal a first World Cup win.
After stacking his bench with six forwards to counteract Georgia's power up front last week, Lagisquet has restored an extra back to his replacements for Sunday's game.
Portugal will need to beat Australia and Fiji to stand a chance of progressing to the quarter-finals, a tall order despite their bright displays so far.
Australia face an embarrassing first-ever pool stage elimination and must win this match and hope Fiji slip up in their final two games against Portugal and Georgia.
"We know we are not as powerful as the Australian team, far from that. But we need to keep a good balance between power and the way we can move," Lagisquet said.
Portugal have caught the eye in the tournament and such has been Australia's woeful form, there is a school of thought that the Wallabies could be there for the taking.
"It's incredible. I'm sure you would never have asked this at the beginning of the competition, now everybody is asking," Lagisquet said.
"They are the two-time world champions. They are a very strong side with very good players.
"We must just keep focused on what we can do and not think that we have a good chance to win. We have to compete like we did against Wales and we'll see what happens.
"If we are very lucky, maybe we will have a little chance."
15-Nuno Sousa Guedes, 14-Raffaele Storti, 13-Pedro Bettencourt, 12-Tomas Appleton (captain), 11-Rodrigo Marta, 10-Jeronimo Portela, 9-Samuel Marques, 8-Thibault de Freitas, 7-Nicolas Martins, 6-David Wallis, 5-Martim Belo, 4-Jose Madeira, 3-Diogo Hasse Ferreira, 2-Mike Tadjer, 1-David Costa
Replacements: 16-Francisco Fernandes, 17-Duarte Diniz, 18-Francisco Bruno, 19-Steevy Cerqueira, 20-Rafael Simoes, 21-Joao Belo, 22-Joris Moura, 23-Manuel Cardoso Pinto
(Reporting by Nick Mulvenney and Nick Said, editing by Ken Ferris)