A Tyrone Roberts-inspired Newcastle Knights defied the odds in the second half to upset the Sydney Roosters 16-12 at Hunter Stadium on Friday night.

Down 6-0 at halftime and without injured skipper Jarrod Mullen (abdominal strain), the 14th-placed Knights led 10-6 in the 63rd minute after two tries from Roberts.

The defending premiers took back the lead 12-10 in the 71st minute through a scrappy Frank-Paul Nuuausala try but Roberts came up with the matchwinner, kicking for Joey Leilua to score with just over a minute remaining.

The shock defeat leaves the Roosters’ title aspirations in plenty of doubt – this was their third loss to a team currently in the bottom four including just two games after being run down by the bottom-of-the-table Cronulla.

Newcastle, missing six regular first-graders, had drawn level when Roberts put Beau Scott through with a flat pass then backed up on the inside to score in the midway through the second half.

Dane Gagai converted, but only after Jared Warea-Hargreaves was given 10 minutes in the sin-bin for dissent.

Roberts was in again three minutes later when Willie Mason burst into the clear, recovered from a failed tackle and offloaded.

Gagai, though, missed an easy attempt at goal to leave the door open for the fifth-placed Roosters.

Nuuausala took advantage to score a lucky four-pointer with less than 10 minutes to go, Sonny Bill Williams offloading close to the ground and Nuuausala inadvertently kicked it through and regathered to score.

James Maloney added the extras to put the visitors back in front before Roberts and Leilua responded.

In the first half, a penalty for a Willie Mason high shot put the Roosters in position early and they capitalised in the second minute when 18-year-old Sione Mata’utia made a horror start to his NRL career.

The fullback, on debut in place of Darius Boyd who is seeking treatment for depression, slipped over attempting to gather a Jake Friend grubber to gift Anthony Minichiello a try in the second minute.

The Roosters dominated the rest of the half, getting over the line three times but having no success against a scrambling defence.

Mata’utia gained some redemption for his early howler with a desperate chase to force a knock-on from Maloney in the 15th minute after the pair sprinted to a deflected Gagai kick.

The video referee’s decision to overturn the onfield try was puzzling, while desperate defence from Robbie Rochow denied Maloney soon after.