Cristiano Ronaldo added goal number 901 to his sensational career tally to complete a last-gasp Portugal comeback in their 2-1 win over Scotland in the UEFA Nations League.

The former Manchester United and Real Madrid star followed up efforts from Bruno Fernandes and Scott McTominay to prolong the Selecao's perfect start to League A Group 1, leaving Steve Clarke's spirited troops crestfallen in the process.

Despite becoming the first verified man in history to reach 900 professional goals against Croatia in midweek, Ronaldo was dropped to the bench for the Estadio da Luz encounter, a move that did not initially pay dividends for Roberto Martinez.

Indeed, Scotland took a shock lead through their own clinical talisman in Scott McTominay and somehow made it to halftime with their advantage intact, despite a barrage of attacks from a sea of desperate red shirts.

A Portugal equalizer appeared inevitable, though, and so it proved when Bruno Fernandes's scuffed attempt found the bottom corner with a helping hand - or two - from the previously impenetrable Angus Gunn.

The hosts unsurprisingly looked the more likely to nab the game's critical third goal, and so it proved when substitute Ronaldo was presented with an open goal to tap the ball into with just two minutes remaining.

The 901-goal striker had just been denied by the woodwork two times in quick succession before triggering Lisbon pandemonium, which momentarily spilled over onto the field in an unsavory manner as a pitch invader attempted to obtain a selfie.

That breach prompted further and relevant questions about stadium security, but the Portugal party quickly began soon after, and things are already looking ominous for Scotland in the Nations League big time.