Saturday's 42-19 result at Suncorp Stadium came after convert Lomax was ruled out less than an hour before kick-off due to hamstring tightness.
That mattered little to the visitors, who finally converted a good start into victory after four losses this season despite leading at halftime.
They improved to 2-5 while the Reds fell to 4-3, their second-straight loss dropping them to sixth when victory could have shot them into third place.
The Force had lost 11 of their last 12 games and 22 of their last 24 on the road, while the Reds had won nine of their last 11 encounters.
Force flyhalf Ben Donaldson excelled up against Reds No.10 and Wallabies rival Carter Gordon, running incisive lines and kicking potently both in-play and off the tee.
Argentinian lock Franco Molina, in for injured Force skipper Jeremy Williams, had a night out with a first-half double and several clutch lineout plays before rolling over for his third try after the final hooter.
Force fullback Mac Grealy also impressed against his former side, scoring a try after terrific build-up, while his opposite Jock Campbell was one of many Reds who struggled.
Teenage Reds winger Treyvon Pritchard lasted less than 10 minutes into his starting debut, failing his Head Injury Assessment after copping a knock when making a cover tackle.
Force prop Tom Robertson followed him soon after when he was caught out of position tackling Tim Ryan.
And Force winger Darby Lancaster limped off with a lower leg injury after leaping over Campbell to catch a Donaldson bomb and put his side ahead 28-12.
A late 80-metre effort, finished by Reds winger Filipo Daugunu, looked likely to deny the Force their first bonus-point win over the Reds since 2012 before Molina's third after the siren.
Lomax watched it all from the sidelines after pulling up sore following Thursday's main session in the latest twist to the winger's rollercoaster year.
The 26-year-old lit up the NRL during stints with St George Illawarra and Parramatta before walking away from a lucrative Eels contract with the intention of joining R360.
That was flipped on its head when the rebel league's entry was postponed, with Lomax's subsequent bid to join the Melbourne Storm ending in an out-of-court settlement ahead of a potential NSW Supreme Court hearing last month.
Rugby Australia signed the Test and NSW State of Origin star on a two-year deal with next year's home World Cup the obvious carrot.
Lomax has trained for two weeks in Perth and was set for minutes off the bench on Saturday before the hiccup, which is believed to be minor.
Instead he'll target a debut in Fiji against the Drua next weekend.
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