Flanker Dan Lydiate admits he's nervous about whether he will be selected by coach Warren Gatland for Wales' clash with Australia next Saturday.
Wales have not beaten the Wallabies since 2008, losing eight games in a row, with half of those defeats by three points or less.
Lydiate finds himself in a battle with captain Sam Warburton, Justin Tipuric and Toby Faletau for a back row berth.
"I wasn't too happy with my game against Tonga," said Lydiate.
Flanker Lydiate played in Wales 17-7 victory against Tonga at the Millennium Stadium on Friday night.
But the Racing Metro back rower admits he is not sure he played well enough to earn a place against the Wallabies.
"There is always massive competition for back-row places," Lydiate said.
"With Sam playing six against Argentina, 'Tips' at openside, there's Toby at eight and Ryan [Jones] had a good game against Tonga.
"You try and put yourself in a position where you think people will run at you, and they don't, so you end up a lot of the time running around covering space.
"Sometimes everything clicks, sometimes it doesn't, and you get frustrated as a player.
"We will most definitely all be biting our nails when it comes to selection for next week. That's the thing with 'Gats' [coach Warren Gatland], you never know which way he is going to go."
Wales are looking for a major southern hemisphere scalp before beginning their defence of the Six Nations title in February.
While Wales struggled against Tonga, Australia have beaten Ireland and Scotland since losing to England on 2 November.
Lydiate, who would have been an automatic choice in Gatland's back-row not so long ago, knows the emergence of Ospreys openside Tipuric has increased the competition in the Wales back row.
Tipuric has packed down alongside captain Sam Warburton and number eight Toby Faletau when Wales beat England and Argentina by record margins.
Wales had a frustrating evening against Tonga, scoring early tries through centres Owen Williams and Ashley Beck, but then failed to score another point in the remaining 55 minutes.
"Tonga were tough opponents and turned us over a lot, but we had quite a young side out," added Lydiate.
"We have been in this situation before - in 2010 when we drew with Fiji, and Samoa last year, when we lost - so it shows we have progressed.
"Australia is a massive Test for us. We know our history against them, and we will definitely be putting the work in this week."