South Sydney Rabbitohs made it eight NRL wins in a row with a dramatic 21-20 triumph over North Queensland Cowboys, but Sunday's victory came at a significant cost as Greg Inglis suffered a fractured thumb, ruling the Queensland Maroons captain out of State of Origin III.

A 79th-minute drop goal from Adam Reynolds - who had earlier moved up to second place on the Rabbitohs' all-time goalscorer list with a first-half conversion - secured the narrowest of victories for South Sydney at Barlow Park.

The Bunnies have now won eight matches in succession for the first time since 1989, though their latest triumph was soured by the injury to Inglis.

Queensland had been set to name their team for this year's final Origin fixture at 7pm local time on Sunday, but were forced to delay the announcement following Inglis' injury, which is set to rule the veteran centre out for several weeks.

Having already lost the three-match series, the Maroons will be aiming to restore some pride at Suncorp Stadium on July 11.

South Sydney sit second on the NRL ladder, two points behind the table-topping St George Illawarra Dragons, while the Cowboys remain 15th having won just four matches all year.

Sunday's other fixture saw Gold Coast Titans beat Wests Tigers 30-12 to join their opponents on 14 points and boost their flagging top-eight hopes.