The Pirate Ship upset the odds to come away from Wembley with a 2-1 win on Thursday evening, while the Boys in Green were also successful on their travels, sinking Finland by the same scoreline in League B Group 2.
Match preview
A mere 24 hours before kickoff on Thursday evening, news broke of the tragic death of former Greece international and Sheffield United right-back George Baldock, leading the 2004 European champions to request the postponement of their Nations League clash with England.
The Pirate Ship's wish was not granted by UEFA, but in the most fitting tribute to their late teammate possible, Ivan Jovanovic's men - donning their black armbands - played England off the park and deservedly beat the two-time European finalists for the first time.
A second-half double from Vangelis Pavlidis either side of a Jude Bellingham leveller prolonged Greece's perfect start to the 2024-25 competition, and they now lead the way at the top of the rankings by three points, having also conquered Finland and Sunday's visitors last month.
In League B, only first place will do for automatic promotion to the top tier - where Greece are yet to compete - but the Pirate Ship have more than demonstrated their League A credentials, just a couple of years on from finally making it out of League C.
Including a friendly success over Malta in June, Sunday's hosts are now on a four-match winning streak in all tournaments - their last three of which have come under new boss Jovanovic, who extended his 100% record at the expense of Lee Carsley's in midweek.
Victory for Greece on Sunday would see the former continental champions win five games on the spin for the first time since 2016, but Ireland head to Piraeus with a spring in their step following their own triumphant travails on their travels on Thursday night.
The Boys in Green squared up to a Finland side who had also been beaten in both of their opening fixtures last month, and the Scandinavians were on course to make it third time lucky when Joel Pohjanpalo opened the scoring, only for Robbie Brady to inspire a second-half turnaround.
The Preston North End winger assisted Liam Scales's leveller before popping up with an 88th-minute winner, cementing Ireland's spot in third place in the League B Group 2 standings, which would see them contend a promotion/relegation playoff in early 2025.
The beating of Finland marked a maiden victory as Ireland head coach for Heimir Hallgrimsson, as well as a first-ever win away from home in the Nations League for the Boys in Green, but they have never achieved back-to-back triumphs in the competition.
Sunday's visitors were also outplayed by their hosts just over a month ago, falling to two second-half goals in a 2-0 loss to Greece in Dublin, which made it five defeats and one draw for Ireland in six previous meetings with Greece - they have only managed to score once against the Pirate Ship in that time too.
Greece Nations League form:
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Greece form (all competitions):
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Republic of Ireland Nations League form:
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Republic of Ireland form (all competitions):
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Team News
Greece head coach Jovanovic will be forced into a defensive switch for Sunday's contest, as centre-back Konstantinos Koulierakis - who set up Pavlidis's first against England - picked up his second booking of the tournament and must now serve a one-match ban.
Pantelis Hatzidiakos and Panagiotis Retsos will vie to replace their suspended teammate, and there is also a question mark over Liverpool left-back Kostas Tsimikas, who sat out the win on Thursday due to illness.
In an ideal world, Jovanovic would put out an identical XI to the one that stunned the Thrree Lions, although jellied legs could tempt the hosting manager into promoting Dimitrios Pelkas or Petros Mantalos to the forward line.
As for Ireland, Hallgrimsson lost Cardiff City defender Callum O'Dowda to injury before the win over Finland, but the Boys in Green are otherwise in good health for the long journey to Piraeus.
The visiting manager made four changes to the side that last lost against Greece for Thursday's game, one of which saw Brighton & Hove Albion hotshot Evan Ferguson introduced into the first XI as he bids to revive a recently stalled career.
Ferguson had an early goal disallowed but otherwise struggled to fashion any gilt-edged chances for himself, so Adam Idah and Troy Parrott are both alternative options for Sunday's match.
Greece possible starting lineup:
Vlachodimos; Rota, Mavropanos, Retsos, Giannoulis; Kourbelis, Siopis; Masouras, Bakasetas, Tzolis; Pavlidis
Republic of Ireland possible starting lineup:
Kelleher; O'Shea, Collins, Scales, Brady; Cullen, Knight; Ogbene, Azaz, Szmodics; Ferguson
We say: Greece 2-0 Republic of Ireland
With all due respect to Finland, the Scandinavian side have been leaky at the back for a good 12 months now, and a Greece outfit in Piraeus are a much different kettle of fish for the Boys in Green.