The Dragons were flying when they tamed the Roosters on Anzac Day, but the Chooks have basically been on a steady incline of improvement since that round eight meeting, while the Dragons have had a few chinks in the armour exposed.
Last week's trouncing of Manly lifted the Roosters into the top four – one win behind the Dragons – and they have clearly emerged as a serious title contender over the past month or so after taking half the season to click into gear.
Latrell Mitchell has become one of the game's elite players, James Tedesco looks very comfortable at the back, while Luke Keary and Cooper Cronk have developed an effective scrum base partnership.
The Dragons answered a few questions last week, beating the Cowboys in Townsville after some recent ordinary performances. Tyson Frizell missed the game through injury and the Dragons hope he returns to face the in-form Chooks.
Key match-up: There's plenty of compelling head-to-head clashes all over the paddock but it's impossible to go past the battle of the playmakers – Keary and Cronk versus Dragons duo Gareth Widdop and Ben Hunt. The Cronk-Keary combo took time to gel compared to how Widdop and Hunt immediately clicked, but all four are crucial to how far their respective sides go in September. Keep an eye also on the duel between NSW Origin teammates Frizell and Boyd Cordner.
Roosters v Dragons - Round 20
For the Roosters to win: They will almost certainly face a much stiffer defensive wall than they did against Manly but the Roosters should try to play the same way. That means rejuvenated Jake Friend continuing to make smart choices from dummy-half and Tedesco terrorising the Dragons with his ability to back up any line breaks.
For the Dragons to win: We should soon know if last week's win snapped the Dragons back to premiership-winning form or if it was mere fool's gold. Defence will be a big key, especially out wide on Mitchell and Daniel Tupou, while the forwards have to win the battle with their Roosters counterparts to provide Hunt and Widdop with space to create.
Roosters Stat Attack: The Tricolours have lost all three games against their fellow top-four teams this season, but what better time to end that streak than in coach Trent Robinson's 150th NRL game.
Dragons Stat Attack: St George Illawarra are aiming to defeat the Roosters twice in a season for the first time since their premiership-winning run in 2010.
And another thing: Acrobatic winger Nene Macdonald will be a notable absentee for the Dragons on Sunday. Macdonald suffered a foot injury in the round 18 loss to the Tigers and is scheduled to return in the round 21 home game against the Warriors. The winger scored two of his team's four tries when the Dragons beat the Roosters 24-8 on Anzac Day.
Roosters: In a late change, Issac Liu will start the match in jersey (No.14) with Ryan Matterson dropping back to the bench. Isaac Liu and Mitchell Aubusson return on the bench for Lindsay Collins and Nat Butcher. Kurt Baptiste and Nat Butcher were the two players left out an hour before game time.
Dragons: Tyson Frizell returns, with Luciano Leilua dropping to the bench and Blake Lawrie to the reserves. Blake Lawrie and Jai Field were the two players left out an hour out from kick-off.
Head-to-head: Played 38; Dragons 20 wins, Roosters 17 wins, 1 draw
Previous result: Dragons won 24-8 at Allianz Stadium in round 8
Points per game: Roosters 22.1; Dragons 24.5
Points conceded per game: Roosters 14.6; Dragons 17.6
Televised: Live on Nine, Fox League
Peter Civoniceva's prediction: This game of the round between two of the competition's top teams should be a cracker. They're both playing good footy and it's tough to separate them and pick a winner. The Dragons had a good win over the Cowboys and look like they're playing with confidence, but I'm leaning towards the Roosters in a very close game. Latrell Mitchell has taken his game to another level after playing Origin footy and they just look like a side that is getting better each week at the right end of the season.
Tip: Roosters by 4