Kansas City Chiefs defensive coordinator Steve Spagnuolo launched into a furious rant during Super Bowl LIX, as quarterback Patrick Mahomes struggled during the first half.

The Philadelphia Eagles had already stormed into a 24-0 lead at halftime after Mahomes' huge error, throwing an interception that led to a pick-six touchdown from Cooper DeJean.

And their defensive coach Spagnuolo couldn't contain his frustration when referee Ron Torbert penalised the Chiefs with a damaging 15-yard penalty while the Eagles were on offense.

Nick Bolton was penalised after it was deemed that the Chiefs linebacker had committed a 'personal foul' on the Eagles star running back Saquon Barkley.

Torbert announced on the PA: "After the play was over, personal foul for unnecessary roughing... No. 32, 15-yard penalty."

The coach gestured a 'two' with his fingers, suggesting it should have been the same punishment for the Eagles.

He then appeared to say: "Are you kidding me?" before burying his heads into his hands and flying into a rage, ranting: "Are you f***ing s***ing me?"

The incident summed up a nightmare first half for the NFL champions, with Mahomes registering just 20 passing yards and being sacked three times behind the fiery Eagles defense.

The 29-year-old's worried expression said it all after he threw an interception, which led to a superb 38-yard run from birthday boy DeJean.

He was also outclassed by his fellow quarterback Jalen Hurts, who unlike Mahomes was at the centre of everything they created. Hurts passed for one touchdown for A.J Brown, as well as opening the scoring with a one-yard rush.

Fans took up the opportunity to roast Mahomes for his dismal performance, with many claiming the three-time Super Bowl winner couldn't hold a candle to Tom Brady.

Robert Griffin III, the former quarterback for the Washington Redskins (now Commanders), claimed he had never seen Mahomes struggle so badly.

Writing to his 2.2 million followers on X (formerly Twitter), Griffin said: "Never seen Patrick Mahomes play this bad."