Saturday night victories by North Queensland and Sydney Roosters created a three-way tie at the top of the NRL ladder, but both contenders suffered potentially catastrophic injury setbacks that have turned the 2015 premiership picture on its head.

The Cowboys overcame a sleepy start in Auckland, scoring a half-century of unanswered points after letting the embattled Warriors get out to a three-try lead.

But their resounding 50-16 comeback win was overshadowed by Origin stars James Tamou and Michael Morgan leaving the field via medicab during the first half.

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The Roosters, meanwhile, held on for a courageous 12-10 triumph over deposed ladder-leaders Brisbane in the best game of the season, despite losing forward-pack cornerstone Jared Waerea-Hargreaves to an ACL injury and halfback and co-captain Mitchell Pearce to a hamstring tear during the opening 40.

Jared Waerea-Hargreaves’ season is over after an ACL injury. Photo: Getty

Play was held up for more than 10 minutes as Tamou – who battled neck problems earlier this year – was placed in a neck-brace. Early scans revealed no serious damage, but he is no certainty to be on deck before the finals.

Morgan’s fitness is the Cowboys’ big worry, however, with scans on a suspected high ankle sprain to determine whether the gun five-eighth will be back at all this year.

The Cowboys can adequately cover Tamou’s absence; former Test prop Ben Hannant can move up to start alongside Matt Scott, while tyros Ben Spina and Coen Hess showed enough at Mt Smart to indicate they can fill any gaps on the bench.

But choosing a new No.6 will provide coach Paul Green with a more uncomfortable sleep than the Townsville humidity.

Does he reshuffle in-form fullback Lachlan Coote, an experienced pivot, and hooker Jake Granville, a former fullback, and bring utility Rory Kostjasyn into the starting spine? Or recall one of out-of-favour duo Robert Lui and Ray Thompson, who boast just 10 first-grade appearances between them in 2015?

Legends and Sunday Footy Show pundits Peter Sterling, Andrew Johns and Brad Fittler were already prepared to declare the Cowboys’ title hopes dead and buried if Morgan is ruled out for the year, even considering the ubiquitous talents of the code’s No.1 player, Johnathan Thurston.

The extent of Greg Inglis’ knee injury is unclear. Photo: Getty

The trio were equally sceptical about the Roosters’ chances without Pearce, whose early prognosis has him sitting on the sidelines for four to six weeks – in more significant terms, returning any time between the second week of the finals and the grand final.

A perennial whipping boy at Origin level, Pearce has proven time and again his importance to the Tricolours. Versatile 19-year-old Jackson Hastings, who will partner Pearce on a permanent basis when James Maloney departs for Cronulla, is the player who will step into the playmaking hot-seat.

Waerea-Hargreaves’ season-ending injury is a heartbreaker for player and club – the aggressive Kiwi has been in irresistible form and appeared set to carry the Roosters to their second title in three years on his broad shoulders.

But the rousing performances of young enforcers Dylan Napa, Kane Evans and Sio Siua Taukeiaho in Saturday night’s epic win emphasised the Roosters’ depth up front. Sam Moa is also due to return next week, while rugged mid-season acquisition Suaia Matagi is waiting in the wings.

The Roosters’ continuity and charmed run with injury has been central to their success under coach Trent Robinson, and this shapes as the squad’s biggest test in three seasons.

Greg Inglis sent shockwaves through the South Sydney camp when he hobbled off after his troublesome knee flared up in the Rabbitohs’ disappointing loss to Canterbury, but the early reports are that he will be ready for Thursday’s blockbuster with the Broncos. Souths’ 26-12 defeat could see the defending champs slide out of the top four by the end of the round.

The Broncos may have surrendered their minor premiership lead at a crucial juncture, but in light of their rivals’ misfortune, Wayne Bennett’s side may have emerged from the weekend’s carnage further ahead in the race for grand final glory.