Not content with just the 900 career goals, Cristiano Ronaldo remains on a mission to breach the 1,000 mark and inched ever closer to that unparalleled milestone on Saturday, doubling Portugal's lead against Poland after Bernardo Silva broke the deadlock.

Even though Piotr Zielinski cut the deficit in half for Poland to ostensibly set up a tense finale, his effort was cancelled out by one of his teammates, as Jan Bednarek diverted the ball into his own net in the dying embers to restore Portugal's comfortable advantage.

Now three for three in the 2024-25 competition, having flexed their muscles against Croatia and Scotland in September, the 2016 European champions are three points clear at the top of the section and can wrap up a quarter-final place with a win if other results go their way.

Should Portugal prevail in Glasgow, the only scenario in which they would be forced to wait to confirm a top-two finish would be if Poland defeat Croatia - leaving both sides on six points and Portugal on 12 - although Martinez's men would then need to lose both games in November to drop out of the knockout berths.

Such a scenario is unthinkable for the Selecao, who are the only team in the four League A groups with a perfect record of nine points after three games, although they did not get the better of Tuesday's foes without a major scare in September.

Indeed, Steve Clarke's men were in the ascendancy after just seven minutes against Portugal last month thanks to international goal machine Scott McTominay, only for Bruno Fernandes and the inevitable Ronaldo to turn the tie on its head.

Scotland were consigned to an identical fate against Croatia on Saturday evening, as after Ryan Christie drew first blood in Zagreb, Clarke's crop failed to cling onto their advantage once again as Igor Matanovic and Andrej Kramaric propelled the 2018 World Cup finalists to a comeback success.

Che Adams's last-gasp leveller being disallowed for offside rubbed salt into the wounds for Scotland, who have not been blown away by any of their League A foes thus far, but the pointless hosts are heading straight back down to the second tier barring a miraculous turnaround.

Draw or lose on Tuesday and Scotland can more or less kiss their wafer-thin top-two hopes goodbye, and it is now four successive defeats for Tuesday's hosts, whose only win in their last 15 games came against minnows Gibraltar in a summer friendly.

September's agonising loss to Portugal also made it four straight defeats to the Euro 2016 winners for Scotland, who have not conquered their upcoming visitors since 1980, where Kenny Dalglish was among the scorers in a 4-1 European Championship crushing.

Portugal came through their triumph over Poland unscathed on the physical front, although Sporting Lisbon centre-back Goncalo Inacio withdrew from the ranks with an injury before the October internationals began.

Joao Palhinha - who has experienced a difficult start to life at Bayern Munich - Francisco Conceicao and Tomas Araujo were all omitted from the matchday squad at the weekend, although those were tactical decisions from Martinez, who had to leave three of his troops out.

With Inacio and Araujo out, Chelsea's Renato Veiga began at centre-back on his full debut for Portugal's senior team, although Antonio Silva is now an alternative option if jellied legs come into play.

Scotland also have no fresh concerns to report from their narrow defeat to Croatia, prior to which Angus Gunn, Lawrence Shankland and Greg Taylor all pulled out with injuries, in addition to Celtic winger James Forrest.

Almost neck-and-neck on the appearances front, Andrew Robertson (77) and veteran goalkeeper Craig Gordon (76) should add another cap to their CVs on Tuesday, where the former would overtake Alex McLeish for fourth all-time.

Despite seeing his last-gasp equaliser in Zagreb disallowed, Adams - who has six direct goal contributions from his first nine appearances in a Torino shirt - is certainly a candidate to replace Lyndon Dykes at the tip of the attack.

Scotland possible starting lineup:

Gordon; Ralston, Souttar, Hanley, Robertson; McLean, Gilmour; Doak, McTominay, Christie; Adams

Portugal possible starting lineup:

Costa; Dalot, Dias, Veiga, Mendes; Silva, R. Neves; Jota, Fernandes, Leao; Ronaldo