Kalyn Ponga gave a glimpse of the impact he could have at five-eighth for Newcastle this season by laying on two tries as St George Illawarra unearthed Fiji wing sensation Mikaele Ravalawa in their trial on Saturday.

The match, which was shifted to WIN Stadium due to problems with the playing surface at the Dragons' home ground, Netstrata Jubilee Stadium, was the first chance for Newcastle coach Nathan Brown to pit his new halves pairing of Ponga and Mitchell Pearce against NRL opposition.

St George Illawarra also fielded a new-look spine, with captain Gareth Widdop shifting to fullback in the first half to accommodate off-season recruit Corey Norman at five-eighth.

Norman started alongside his former Brisbane halves partner Ben Hunt, while Cameron McInnes started at hooker.

The rival spines, which included Connor Watson at fullback for Newcastle and Danny Levi at hooker, played the opening 40 minutes of the trial, with Ponga making the greatest impression in his move from fullback to five-eighth.

The 20-year-old, who won the 2018 RLPA player of the year and was runner-up in the Dally M awards, was able to get his hands on the ball a lot more and created both of Newcastle's first-half tries.

The first came when he put Lachlan Fitzgibbon through a gap on the left edge and the back-rower stepped inside Widdop to score in the 18th minute. Ponga converted to level at 6-6.

Another short ball from Ponga created space for Fitzgibbon and he swivelled in a tackle before linking with Pearce, who put winger Edrick Lee over in the corner in 28th minute.

In comparison, the Dragons' key players appeared to be adjusting to the positional changes, with Matt Dufty arguably more impressive than Widdop at fullback after replacing him in the second half.

Indigenous All Stars prop Josh Kerr was also impressive in the second half for St George Illawarra, while Ravalawa proved a revelation on the right wing after joining the Dragons from Canberra this season and scored two tries.

St George Illawarra coach Paul McGregor started the match with star rookie Zac Lomax in that position but Lomax shifted into the centres in place of Euan Aitken, who also spent time at left centre.

NSW Origin prop Paul Vaughan made a successful return from a leg injury that ended his 2018 season and scored the opening try in the 14th minute when he ran over the top of Levi.

Trailing 10-6 at halftime, the Dragons dominated the scored half and scored three unanswered tries, while bombing or having others disallowed.

Kerr crashed over in the 57th minute and Ravalawa scored his first try nine minutes later after receiving a cut-out pass from Dufty and stepping inside four defenders to score.

The Fijian winger claimed his second try in the 78th minute to secure the Dragons 18-10 win and could solve McGregor's dilemma over a replacement for departed winger Jason Nighingale (retired) and Nene Macdonald (North Queensland).