The Australian was just over a tenth off the pace of team-mate and pole-sitter Lando Norris at the end of the abridged qualifying session on Friday night.
His best of 1:21.171s marked a 1.3s gain from Free Practice 1 and a more-than three-second gain over the same session a year ago.
“Reasonably happy,” Piastri said of his qualifying session.
“Wasn’t the greatest lap of my life but I think with these conditions it’s very tough and I’m pretty sure everybody will be saying that.
“Struggling a little bit at the start but I felt like I was in the groove at the end, just very fine margins.”
Piastri had been third fastest in the opening practice hour, all but matching Norris in second though the pair four-tenths shy of Charles Leclerc’s Ferrari.
Blustery conditions hampered drivers in that practice hour, though eased somewhat as the evening wore on.
The temperature had dropped too, and hovered at just 20 degrees as Sprint Qualifying began.
“To be honest, [it] wasn’t too different to practice,” Piastri said of the conditions across the two sessions.
“The wind has dropped a little bit, makes the car a little bit easier to drive, but everything’s a bit easier than it was 12 months ago here.”
Piastri started on pole in last year’s Sprint, going on to win the encounter following a battle with George Russell.
He then withstood pressure from Max Verstappen to take what was his first F1 success.
“This track’s pretty mega to drive around,” he said.
“There’s a lot more grip this year than last year so the high-speed sections are a lot of fun.
“It’s a really awesome track,” he added.
“Especially the highspeed section, which is pretty much most of the track. It’s a lot of fun out there.”
The Qatar GP Sprint begins at 17:00 local time on Saturday (01:00 AEDT Sunday)