After facing intense scrutiny following a sluggish opening draw, 41-year-old Cristiano Ronaldo hits a historic Uzbekistan double to remind the world never to write him off.

Cristiano Ronaldo declared "I'm back" and insisted those "attacking" him should never write him off after making World Cup history in a 5-0 hammering of Uzbekistan on Tuesday in Houston.

The 41-year-old, under immense pressure to deliver after a barren recent run at major tournaments, pounced after just six minutes to become the first player to score in six separate Fifa World Cup campaigns. He added a second with a smart finish before half-time as Roberto Martínez's side ran riot against limited opposition.

The five-star display was in stark contrast to a stale 1-1 draw with the Democratic Republic of Congo in their opening fixture, a match in which Ronaldo looked laboured and largely anonymous. That performance sparked renewed calls in some quarters for Martínez to drop his veteran captain, with Ronaldo, the coach, and the national squad all facing heavy flak back home.

Ronaldo shouted "I'm back, I'm back" directly into a television camera after his two-goal display.