The 29-year-old discovered he was eligible to represent the Republic of Ireland in 2014 after investigation into his family tree, then promptly produced two assists on an eye-catching debut - a 4-1 home win over the USA.
The Tartan Army beat Slovakia on Thursday courtesy of a late own goal, and have leapfrogged their opponents into second place in Group F. As long as they beat Slovenia on Sunday they will be guaranteed second place, and will have 14 points in the play-off table, which should be enough to guarantee a top-eight finish.
But the other home nations are all fighting hard to join them at the 2018 World Cup.
Scotland found a massive 89th-minute goal to secure a 1-0 win over 10-man Slovakia and put themselves in pole position for the playoffs.
Only two wins from two will offer Martin O'Neill's men - who now lie in third in Group D, behind second-place Wales - a chance at making it to the play-off round, with it still far from certain that the runners up in our group will make it through given that just eight of the best runners-up across the nine European groups enter the draw.More news: Hillary Clinton's Response to Las Vegas Shooting Calls for Gun Control
Hovhannes Hambardzumyan struck back for Armenia, who are already out of contention, but in the second half Jakub Blaszczykowski added another and Lewandowski netted his 50th global goal to seal his hat trick from close range.
Games remaining: October 5 v Slovenia (h), October 8 v Lithuania (a). There were some mistakes, we conceded some goals. Knowing that the star of the side that stands between the boys in green and second place in the group won't be playing is as good as it gets.
That would leave Ireland on 19 points from ten games and secure in second place - assuming Serbia pick up at least one point in their last two games. It remains to be seen if he will recover in time for Cardiff on Monday.
Let's assume England qualify outright and Northern Ireland, Scotland and one of Wales or the Republic of Ireland do make the play-offs. They could still reach the play-offs if they pick up four points but that would mean even more reliance on other results.
Speaking about the new deal, O'Neill said: "I spoke to John (Delaney) very recently and he said on behalf of the board that they would like to extend my contract for another couple of years obviously with the Euros coming up".