Wales overcame Fiji 23-13 in a bruising Cardiff contest to move to the top of Pool A, but a quarter-final place remains far from certain for Gatland’s men despite them winning their first three group games.
England beating Australia on Saturday night would throw the race for the two top spots in the pool wide open and probably leave Wales needing to avoid defeat in their final game against the Wallabies to make the last eight.
But an Australia win will send England out and guarantee Wales a place in the quarter-finals.
“It’s hard not to be entirely selfish on Saturday because Australia can do us a big favour,” Wales coach Gatland said.
“We’d make the quarter-finals and it’s hard not to think that way.
“But it’s a bit hard for a Kiwi to be jumping up and cheering for the Aussies! So I think I’ll be quite neutral this weekend.” Wales scored two first-half tries to build a 17-6 interval lead and appeared well set to match the bonus point England managed from their opening game against Fiji.
But the Pacific Islanders showed great tenacity in the second period and reduced the lead to four points when centre Vereniki Goneva rounded off a stunning 60-yard passing movement to score a converted try.
Two Dan Biggar penalties, however, got Wales over the line to keep the momentum going after their stunning triumph over England at Twickenham last weekend.
“It was a really tough physical encounter and I am absolutely delighted with the win,” Gatland said.
“Given that short turnaround we had to dig really deep and I thought the players did well.
“We played pretty well and dominated the first half, and if we’d scored at the start of the second half maybe the game would have opened up a bit more.
“But to me it was about winning the game and the courage we displayed was the most important thing, “We did that last week and it shows the character of this group of players at the moment.” Wales have been hit by serious injury both before and during the tournament, losing no less than five players until now and being forced to call up several replacements.
o Gatland was delighted his squad appeared to have emerged unscathed from their latest physical battle, with knocks to Dan Lydiate, Matthew Morgan and Biggar not thought to be serious.
“There’s a few battered bodies but we look OK at the moment,” Gatland said.
“It will be a normal week for us ahead of the Australia game.
“The boys will have a bit of time with themselves and their families and recuperate before we play Australia and try to win this group.” Fiji will have to qualify for the 2019 World Cup in Japan after three defeats means they will definitely finish outside the top three in Pool A.
But Fiji coach John McKee refused to criticise a punishing schedule which forced them to play England, Australia and Wales in the space of 13 days.
“We knew what it was when we came here,” McKee said.
“I’m not sure of all the ramifications of how you can organise a Rugby World Cup in a certain time frame, and that’s the luck of the draw.
“To play England, Australia and Wales in 13 days is a hard task for any team in world rugby but we’ve stood up to those teams and been really competitive.
“We knew what a difficult pool it was but we had expectations coming here and it’s very frustrating to have no points on the table.
“It was a great Test match in terms of the intensity and to go so close is frustrating.”
Tries: G. Davies, Baldwin. Cons: Biggar 2. Pens: Biggar 3.
M. Morgan, Cuthbert, T. Morgan, Roberts, North, Biggar, G. Davies, Jenkins, Baldwin, Francis, B. Davies, Jones, Lydiate, Warburton, Faletau.
Hook for M. Morgan (72), Priestland for Biggar (73), Jarvis for Jenkins (67), Owens for Baldwin (56), Lee for Francis (53), Charteris for B. Davies (65).
Tries: Goneva. Cons: Volavola. Pens: Volavola 2. Fiji: Talebula, Nagusa, Goneva, Botia, Tikoirotuma, Volavola, Kenatale, Ma’afu, Koto Vuli, Saulo, Cavubati, Nakarawa, Waqaniburotu, Qera, Talei.
Matavesi for Goneva (71), Murimurivalu for Botia (77), Seniloli for Kenatale (70), Veikoso for Ma’afu (76), Atalifo for Saulo (77), Soqeta for Cavubati (71), Ravulo for Waqaniburotu (70).
John Lacey (Ireland).