Die Mannschaft ran out 2-0 winners over Peru in Saturday's exhibition encounter, while Domenico Tedesco's Belgium reign began with a 3-0 success over Sweden in Euro 2024 qualifying.
Match preview
As their fellow European hopefuls fight for the right to join hosts Germany at the next continental championships, Hansi Flick has been presented with bountiful opportunities to trial new players and tinker with his talent-packed squad during a spate of friendly matches.
While Die Mannschaft tested out an unfamiliar 4-2-2-2 setup during the visit of Peru, Los Incas were never expected to pose much of a threat in Mainz, and a first-half double from Niclas Fullkrug did the damage as Flick's men ran out comfortable winners.
The margin of victory could have been greater had Kai Havertz not struck the post from the penalty spot - the Chelsea forward scored the rebound but his effort did not count due to the double-touch rule - as Germany began the New Year as they mean to go on.
Now unbeaten in 13 friendly matches since a 2-1 defeat to near neighbours Austria in 2018, Germany are already being tipped by some as genuine contenders for the Euro 2024 crown - despite their recent failures in the major tournament landscape - and success on the continent is long overdue.
Indeed, Die Mannschaft have not gone all the way at the Euros since 1996 - suffering two semi-final exits and a final defeat to Spain since the turn of the millennium - but Belgium's ageing golden generation have a similar goal in mind.
While a certain Zlatan Ibrahimovic made history as the oldest-ever player to appear in a European Championship qualifying match, Belgium's talismanic number nine soon stole the spotlight as Belgium began their top-two bid in ruthless fashion.
Consigning his infamous World Cup horror display against Croatia to history, Romelu Lukaku's deft header put Belgium into the ascendancy in the first half before a pair of tap-ins clinched the match ball for the Chelsea striker, whose injection of confidence was just what the doctor ordered.
Already cementing a second-placed berth in Group F after one game - Austria have the edge for the time being courtesy of their 4-1 win over Azerbaijan - Belgium temporarily push their competitive commitments to one side as Tedesco seeks to maintain his 100% start in Cologne.
In what was potentially a harbinger of doom, Belgium's last friendly match just before the World Cup ended in a 2-1 loss to Egypt - ending a 17-game unbeaten streak in exhibition contests stretching back to a 1-0 loss to Spain in 2016.
Before establishing themselves as one of Europe's big boys, Belgium were one of Germany's whipping boys, as they are winless in their last 16 matches with Die Mannschaft and could suffer a 10th defeat in a row to their Cologne counterparts here - most recently losing 3-1 in a Euro 2012 qualifier.
Germany friendly form:
W
Germany form (all competitions):
D
W
L
D
W
W
Belgium form (all competitions):
L
L
W
L
D
W
Team News
Germany and Borussia Dortmund were handed a slight scare when Nico Schlotterbeck came off injured in the dying embers of Saturday's win over Peru, but Flick affirmed after the game that the centre-back's removal was only precautionary.
Either Thilo Kehrer or Malick Thiaw should be considered for starts if Schlotterbeck is not risked, though, and Flick should not shy away from making a few more alterations as fringe players try to force their way into the Mannschaft coach's plans on a more regular basis.
Familiar faces in Serge Gnabry and Leon Goretzka are among those who could force their way back into the XI, while Mario Gotze may also benefit from Flick's fresh 4-2-2-2 setup.
As for Belgium, Tedesco did not pick up any injury concerns during their romping victory over Sweden, although the perennially-injured Jeremy Doku was forced to withdraw from the squad before that Scandinavian success.
However, the Belgian FA has agreed to let Thibaut Courtois head back to Real Madrid early given Los Blancos' unforgiving end to the season, so only a fifth cap could come the way of Wolfsburg's Koen Casteels.
Having both assisted Lukaku goals during Friday's win, a fierce battle for supremacy on the right between Dodi Lukebakio and Johan Bakayoko could soon materialise, but the former should continue from the off for the time being.
Germany possible starting lineup:
Ter Stegen; Wolf, Ginter, Thiaw, Raum; Kimmich, Goretzka; Gnabry, Gotze; Werner, Fullkrug
Belgium possible starting lineup:
Casteels; Castagne, Faes, Vertonghen. Theate; Onana; Lukebakio, De Bruyne, Carrasco; Trossard, Lukaku
We say: Germany 2-2 Belgium
Neither Flick nor Tedesco will lose sleep over the result of Tuesday's friendly, where avoiding injury may be the overriding goal for both sets of players before the resumption of their domestic campaigns.