The Western Force have come up clutch for a crucial 20-17 Super Rugby Pacific win over the NSW Waratahs in Sydney.

Former Waratahs pair Dylan Pietsch and Ben Donaldson ultimately upstaged the two code-hopping superstars as they led the Force to their season-saving victory at Allianz Stadium on Friday night.

But, like the excellent Pietsch and Donaldson, Lomax must have given the Wallabies coaching staff food for thought with not only his impressive display under the high ball but also his energy on and off the ball. 

For all the hyped build-up about the brewing "match-up" between the one-time NSW State of Origin teammates, Suaalii and Lomax seldom clashed.

Suaalii still showcased his signature subtle touches, while Lomax caused the Waratahs all sorts of headaches, not only as an aerial threat but also with his clever running game.

But Pietsch and Donaldson were the true stars for the Force, who pulled within two competition points of the eighth-placed Waratahs to keep their top-six finals hopes flickering.

As if slighted by all the focus and attention on fellow winger Lomax, Pietsch played like a man on a mission in an eye-catching two-try display.

And amid much conjecture over the Wallabies' No.10 role, Donaldson once again stood up to showcase his credentials to outgoing national coach Joe Schmidt and the incoming Les Kiss.

Despite multiple opportunities, mostly from the Waratahs, the first try of the night only came 33 minutes into Friday's contest.

Fired-up flyhalf Lawson Creighton dummied, stepped inside and spun over to give the home team a deserved 7-3 lead after Donaldson had opened the scoring with a third-minute penalty goal.

A Sid Harvey penalty extended NSW's' lead before Pietsch willed his way over on the 22nd phase of a relentless Force raid on the stroke of halftime to make it 10-10 at the break.  

Pietsch put the Force back in front when he cashed in on a Donaldson break to bag his second 11 minutes into a frenetic second half.

NSW replacement hooker Folau Faianga made life interesting with a late try - but the Force hung on for the final five minutes to stay in the finals hunt.

Western Force 20 (Tries: Pietsch 2; Cons: Donaldson 2; Pens: Donaldson 2) def NSW Waratahs 17 (Tries: Creighton, Fainga'a; Cons: Harvey 2; Pens: Harvey)

Teams:

Waratahs: 15 Max Jorgensen, 14 Andrew Kellaway, 13 Joseph-Aukuso Suaalii, 12 Joey Walton, 11 Sid Harvey, 10 Lawson Creighton, 9 Jake Gordon, 8 Pete Samu, 7 Charlie Gamble, 6 Angus Scott-Young, 5 Angus Blyth, 4 Matt Philip (captain), 3 Siosifa Amone, 2 Ethan Dobbins, 1 Tom Lambert.
Replacements: 16 Folau Fainga’a, 17 Isaac Kailea, 18 Apolosi Ranawai, 19 Miles Amatosero, 20 Jamie Adamson, 21 Teddy Wilson, 22 Jack Debreczeni, 23 Triston Reilly

Western Force: 15 Mac Grealy, 14 Zac Lomax, 13 George Bridge, 12 Hamish Stewart, 11 Dylan Pietsch, 10 Ben Donaldson, 9 Henry Robertson, 8 Nick Champion de Crespigny, 7 Carlo Tizzano, 6 Jeremy Williams (captain), 5 Darcy Swain, 4 Franco Molins, 3 Misinale Epenisa, 2 Brandon Paenga-Amosa, 1 Tom Robertson
Replacements: 16 Nic Dolly, 17 Sef Fa’agase, 18 Harry Johnson-Holmes, 19 Lopeti Faifua 20 Will Harris, 21 Nathan Hastie, 22 Bayley Kuenzle, 23 Kurtley Beale

Referee: Angus Gardner
Assistant Referees: George Myers, Matt Kellahan
TMO: James Leckie