After surviving Basic's relentless rush by a hair, Eschez pushes back with two squads of Tech 3 Siege Assault Bots. Notice the difference in power between Tech 1 and Tech 3 units. Despite Basic's clear advantage in terms of numbers, Eschez' squads cut through Basic's forces like butter.
Above: Eschez in Basic's base, killing his d00dz
One of Eschez' squads makes a beeline for Basic's main base and quickly exterminates several of his Land Factories, while the other heads towards Basic's secondary base on the west side of the map. While this second squad winds up fizzling out before doing any serious damage, it was enough to force Basic to move his ACU out of harm's way.
Notice how Eschez immediately capitalizes on Basic's decision to move his ACU north of the western base. Once Basic moves his ACU, Eschez aborts his attack on Basic's main base and swoops down, focusing his fire on the ACU. Game over. Eschez wins.