An early two-minute brace from Bayern Munich target Leon Goretzka saw Germany take control of the semi-final in Sochi, where Mexico refused to give up but struggled to cope with the energy and quality of a side derided by many before the tournament as disrespectfully inexperienced.
Rather than find themselves out of their depth in Russia, Low's raw squad have instead served to make a statement of the ominous depth of talent beyond the first-choice ranks of the world champions, typified by striker Timo Werner, who struck his team's third goal shortly before the hour mark. Marco Fabian's blistering late free-kick mattered little for Mexico, a fact hammered home when Amin Younes restored Germany's three-goal cushion in added time.
Germany will now tackle Chile for the second time in the tournament in the decider in St Petersburg on Sunday.
The battle-hardened Copa America holders, penalty shoot-out winners over Portugal a day earlier, have been the only team to trouble Die Mannschaft's tyros in a 1-1 group stage draw earlier this month.
A high-tempo start at Fisht Stadium saw Mexico, perhaps inadvisably, try to take the game to Germany, succeeding only in leaving themselves wide open at the back. Hector Moreno was caught out of position as Bayer Leverkusen's Benjamin Henrichs advanced down the right before passing inside to Goretzka. The Schalke midfielder guided a well-judged first-time shot just inside the post, beyond the reach of goalkeeper Guillermo Ochoa.
Rather than heed that painful lesson, Mexico were cut apart again two minutes later, when Werner made space for himself in front of the opposition's back four before sliding a pass in behind for Goretzka to run on to. The 22-year-old kept his cool to fire the ball across Ochoa and into the far side-netting. It could easily have been 3-0 in the 19th minute, when Ochoa made a good save with his knees after Werner beat the offside trap.
Mexico slowly steadied and grew into the game, calling Marc-Andre ter Stegen into action three times in quick succession soon after the half-hour mark. Brothers Giovani and Jonathan dos Santos had a shot and a header respectively on target following a clever forward pass and subsequent lay-off that sliced open Germany's young rear guard, while Javier Hernandez poked narrowly over the bar under pressure from the on-rushing Barcelona shot-stopper. The Bayer Leverkusen striker then forced Ter Stegen to tip a dipping long-range free-kick over the bar in a strong finish to the half for Juan Carlos Osorio's men.
Mexico threatened first in the second half through Raul Jimenez, but Germany duly asserted themselves, Werner again getting in behind a stretched defence to slide a finish agonisingly across the face of the goal under pressure from Moreno.
The RB Leipzig striker eventually got the goal his efforts deserved, as Germany put the result beyond doubt in the 59th minute. Julian Draxler was the architect this time, playing Jonas Hector into the box, where the Cologne defender squared to provide an easy finish for Werner, who could perhaps have been flagged offside for his position in the build-up to the goal.
Miguel Layun's fierce drive in the 72nd minute needed Ter Stegen to parry the ball behind, while Jimenez crashed a header against the bar as Mexico strove for a consolation goal.
It eventually arrived in spectacular fashion, impressive substitute Fabian unleashing an extraordinary long-range free-kick to breach Germany's determined resistance.
Low's men could not help having the final say, though, Emre Can teeing up fellow sub Younes for his team's fourth goal in a chaotic period of injury time.