Khawaja produced the only hundred of the first round of the Kookaburra one-day competition, finishing 124 not out against Sandgate-Redcliffe at Deagon.
It lifted Valley to 2-275 as they chased down the Gators' competitive total of 8-274, which was dominated by a fine run-a-ball 74 from Lachlan Thompson and 71 from Khawaja's State teammate Bryce Street.
Khawaja's innings came from 108 balls, featuring 12 fours and two sixes, one of which brought up his ton. He and fellow Bulls squad member Lachy Pfeffer (82) put on 176 for the opening partnership, with Valley allrounder Andrew Gode chipping in with 54 from 54 balls. It completed a strong game for Gode who took 4-46 from his 10 overs in the Sandgate innings.
Western Suburbs welcomed back prodigal son Sam Truloff after a year away in Tasmania, with the free-scoring right-hander top-scoring as they overcame a determined Sunshine Coast outfit at Maroochydore.
Truloff's 65 was complemented by a half century to wicket-keeper Isaiah Snell and 48 to evergreen Steve Paulsen as Wests scored 8-259. First-game Scorchers captain Angus Lovell led from the front with a solid 77 from 101 balls, while some late order hitting from John Turnbull (54no from 38 balls) steered the home side to 8-214.
Redlands also greeted the return of a familiar face with allrounder Simon Milenko, back after a lengthy stint with Tasmania, leading the Tigers to a strong win over University of Queensland at Peter Burge Oval.
Milenko top-scored with 83 from 82 balls as the home side chased down University's total of 225. His effort, coupled with half centuries to Leigh Drennan (60no) and Bulls 'keeper Jimmy Peirson (53) saw Redlands comfortably home with 5-226 in the 39th over.
A lone hand from South Brisbane captain Ben Cutting was not enough to prevent Northern Suburbs from taking the points in a closely-contested clash at Norman Gray Oval.
Cutting's 68 from 64 balls got his side to 187 after a concerened Norths bowling effort, led by new ball pairing Sam Hele (3-23) and Connor Sully (3-43) and tight bowling from spinners Nathan McSweeney (2-21) and Nathan Hauritz (1-24).
Norths had to work hard to reach the target with Sully (24no) and Hauritz (21no) getting the Vikings home at 8-188.
Rising Gold Coast allrounders Hugo Burdon and Josh Kann and newcomer Kyle Wisniewski provided match-defining efforts as the Dolphins overcame Toombul by four wickets at Ken Mackay Oval.
Toombul was held to 227, in spite of a fine half century from Harrison McNeilly and a defiant 44 from experienced allrounder Preston White and 38 from club debutant Chris Knight.
Leg-spinner Burdon picked up 3-42 while Tasmanian pace bowling recruit Wisniewski claimed 4-38.
Burdon then top-scored with 71 from 98 balls, with a quickfire 41 from 22 balls by former Queensland Under-19 batsman Jack Cooper and a clean-hitting 68 not out from 51 balls from Kann leading the Dolphins to a first-up win.
At Baxter Oval, Ipswich/Logan opened their season with a sold first-up win over Wynnum-Manly.
The Hornets scored 7-260, with Levi Thomson-Matthews producing a tidy 59 and experienced opener Dan Wilson 49, before restricting the Sea Eagles to 227. Grayson Jones top-scored with 48 for the visitors, as Sean Lutter took the bowling honours with 4-23.
Look out for the weekly video highlights wrap-up later this week to catch up on all the action from the first round of matches.
All men's First Grade and women's First Grade games will be live-streamed this season through the Premier Cricket match centre: https://matchcentre.premier.qld.cricket.com.au/