Khawaja top-scored for the Aussies with 50 as they finished their innings at 236/7.
"Looking back, 250, when we were batting, probably would have been par ... 300 would have been a bit unrealistic on that wicket," Khawaja said.
With the World Cup around the corner, the Australian batting continues to be a cause of concern.
Khawaja came into the ODI side only at the start of the year before being promoted to the top on Saturday. Marcus Stoinis at number 3, Maxwell at 5 and Ashton Turner at 6 were among the changes in an unsettled batting line-up.
Khawaja, Stoinis, Maxwell and Turner all made starts but couldn't cash in, leaving Alex Carey and Nathan Coulter-Nile to bat the final 10 overs.
"I thought the guys played really well. Maxi is in fine touch right now, Stoinis is always playing well.
"It wasn't easy, it was a tough wicket. We were trying to figure out what the best score was.
"We just probably needed a couple more set batsmen ... for the final 5-10 overs."
Australia haven't scored more than 300 in ODIs since last year's tour of England, where they lost all five matches, and they've now had just four wins from their past 25 ODIs.
Khawaja backed his team to post a big total if given the opportunity on a more batsman-friendly pitch in India.
Aaron Finch touched on the issue of Australia's recent modest totals on the eve of the first ODI, noting "if you go out every ODI and try to get 400, I think you're dreaming".
First Published: March 5, 2019, 7:00 AM IST