Usman Khawaja staked a late claim to one of Australia's top-order batting slots despite an injury scare during their five-wicket victory in their World Cup warm-up match against Sri Lanka in Hampshire.

Khawaja hobbled off the field after a ball struck him flush on the left kneecap. He was fielding at mid-off when he dived to his left to stop a ball that had been driven firmly by Jeevan Mendis off the bowling of Steven Smith. Khawaja limped off the field after receiving treatment from the medical staff but was cleared to bat in Australia's innings.

"It's fine, embarrassing more than anything," said Khawaja, after the match. "It just hit the side of my knee and I couldn't put any weight on it. I'd try to get up, Gaz [Nathan Lyon] was telling me to just lie down, but I was saying I'm not going to lie down, I'm going to get up, but I'd try to get up and I couldn't. My knee collapsed underneath me because of where it hit, I went off, iced it and after about 25 minutes I felt all right, it's a bit sore now but nothing structurally wrong.

"When I walked off I was laughing, I was in pain but I knew there was nothing serious about it. It was the same knee I had a reco on, so we were a bit careful about going back on the field just because it was collapsing a little bit but I was alright when I went back out there."

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Opening the batting with Aaron Finch, Khawaja went on to comfortably steer Australia towards Sri Lanka's total of 239 for 8 in the 45th over with an innings of 89 off 105 balls.

Coach Justin Langer has rotated Khawaja, David Warner and Shaun Marsh in their World Cup warm-up matches, as they attempt to settle on their best batting line-up. Warner was left out of the team against Sri Lanka, amid reports he had complained of tightness or soreness to his upper leg, giving Khawaja one last chance to impress selectors before the World Cup kicks off.

Warner's absence during the year-long ban for his involvement in the Newland's ball-tampering scandal allowed Khawaja to cement his place at the top of the order, forming a formidable opening partnership with captain Finch.

But after six warm-up matches played since Warner's return, the final makeup of Australia's batting order is still very much open to interpretation. Khawaja has opened four times and Warner on three occasions, although Warner may have had another opportunity at the top in Hampshire if he hadn't been forced to sit out the match. Khawaja has batted at No.3 once and Warner twice while Marsh - who made 34 off 46 balls before holing out in the deep - has floated between batting at No.3, 4 and 5.

"I do love opening, absolutely," said Khawaja. "That's where I've batted my whole life in one-day cricket. But at the end of the day it is about winning games and doing the best for your team.

"I'd much rather get a duck and win then me get 100 and lose. It doesn't matter what happens, where I play, if I play, if I don't play, if I'm running the drinks, I'm going to try and contribute to the squad.

"I know what the changeroom feels like when you're winning and what it feels like when you're losing and the winning one I'll take any day of the week."

Australia have now won 13 of their their past 14 matches, a streak that began during their tour of India in March and continued through their series against Pakistan in the UAE, and then in their warm-up games against New Zealand in Brisbane and the West Indies, England and now Sri Lanka in England. While Pakistan were not at full strength and the following matches were not official ODIs, such a run will give them welcome confidence as they head to Bristol for their opening World Cup game against Afghanistan on Saturday.

"I thought the Indian series in Australia was, from what I saw from the outside coming into that series - obviously we'd lost a lot of one-dayers before that, was a turning point for us because we probably should've won that series and we didn't," Khawaja said. "But they're one of the best sides in the world and we gave them a real run for their money.

"Then we went over to India and lost the first two games and won the series. We all had that confidence even though we lost the first two games that we could compete and actually beat these guys.

"Once we started doing it we got that winning feeling back. Winning is a habit, we say that a lot amongst the team, hence why we try to win all the (warm-up) games we're playing in, just to keep that habit going. We might've lost that habit before but hopefully we've found it again leading into the World Cup."

Melinda Farrell is a presenter with ESPNcricinfo