After captain Jimmy Peirson posted a memorable ton in his 100th first-class game to guide the Bulls to 307 at the WACA Ground in Perth on Friday, WA crashed to 8-158 in response before bad light ended play.
Bartlett (3-41) spearheaded a 4-12 collapse, which dumped WA from 3-128 to 7-140 after opener Sam Fanning (64) had earlier provided stiff resistance.
"I had a pretty lean year last year, so to be able to come out in game one and have a performance like that, I hold it dear to my heart - in my 100th game as well, which is pretty cool," Peirson said.
"In the space of eight balls, he (Bartlett) turned that on its head and picked up three quick wickets.
"That just shows Xavier's class.
"It was a very disciplined performance from our bowlers."
Cam Bancroft (16) fell to Cameron Gannon before former captain Sam Whiteman came in at No.3, substituting in for Tom Murray, after illness ripped through the WA camp.
Murray himself was handed a first-class debut after original choice Jayden Goodwin withdrew with illness before the toss.
Whiteman (12) and Hilton Cartwright (3) departed cheaply, before Fanning and new skipper Aaron Hardie (33) righted the ship with a 66-run fourth-wicket union.
When Fanning fell to a low, sharp catch by Bartlett at slip off Hayden Kerr, the wheels came off for the home side.
Hardie and Jhye Richardson (0) both nicked off to Bartlett, then Kieran Elliott (7) was trapped lbw by a Mitch Swepson slider in fading light.
Earlier, wicketkeeper Peirson scored 36 of the Bulls' 49 runs in the first session to finish unbeaten on 101, after Queensland resumed at 6-258.
Young WA seamer Albert Esterhuysen (4-43), after being erratic and expensive on the opening day, fought back to tear into the Bulls' lower order, dismissing Bartlett (6) and Swepson (0) in the first four balls of the morning.
Gannon (11), facing his old side after returning to Queensland, proved a useful ally in a 48-run ninth-wicket stand with Peirson, who slashed Joel Paris over the offside to raise his ninth career ton off 144 deliveries.
The Gannon vigil ended when he edged Esterhuysen for Bancroft's 171st Shield catch, surpassing former teammate Adam Voges for the most by a WA fielder.
"It was nice to get a couple of wickets at the end," Esterhuysen said.
"It's a spicy wicket ... cricket's a funny game and you never know what could happen.
"There's still two days of cricket left."
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