The stage begins with a cutscene, in which, Classic Sonic is seen running through Stardust Speedway until Metal Sonic destroys the road. Sonic then uses the falling debris to get back up, along with jumping on top of Metal Sonic. Metal Sonic recovers from the blow and attempts to hit Sonic, but misses. After that, the two begin to battle.
The entire fight is a high-speed chase, with Metal Sonic flying overhead, attacking Sonic. Metal Sonic has a variety of attacks, including the Ring Spark Field, flying into the foreground to snap off street lights to fall on the player, and the V. Maximum Overdrive Attack. After attacking, Metal Sonic becomes vulnerable for a short amount of time, allowing the player to counterattack with a Spin Jump. It takes a total of four hits to defeat Metal Sonic on Normal and Hard mode.
Metal Sonic starts the fight by lunging forward at Sonic, forcing the player to jump out of the way. After being attacked, Metal Sonic will perform a Ring Spark Field attack where he generates a huge amount of electricity around and directly underneath him that Sonic must avoid or attack while he's charging it. Metal Sonic's next attack involves snapping off street lights to throw directly at Sonic; the player must avoid these by watching the shadows of the streetlights on the road. Finally, Metal Sonic will attack with a powered up version of his first attack, which can avoided by jumping up on higher platforms. Once Metal Sonic is given the final blow, there is a brief cutscene of Sonic kicking Metal Sonic away, who proceeds to explode.
In Hard Mode, Classic Metal Sonic is much faster, making it harder to avoid his attacks. The order of his attacks also changes; Classic Metal Sonic snaps a total of five street lights at Classic Sonic before performing his Electric Shield attack, as opposed to two in Normal Mode.
In the Nintendo 3DS version of the Sonic Generations, the battle is a race to the Goal Plate. Based on the player's position to Metal Sonic, the robotic hedgehog will either resort to use the Ring Spark Field or his V. Maximum Overdrive Attack. If the player is before him, he will use the former, but if the player is ahead of him, he will use the later to slowly outpace Sonic.
During the race, Metal Sonic does not seek every shortcut in Casino Night in case the player is not ahead of him or has used them. Also, when the player is near him, they are able to attack him via the Spin Attack to slow him down.
Some of the skyscrapers in the background look similar to the Ionian column design used in Greek architecture (This could be a reference to how Stardust Speedway's past is heavily based on ancient Greece).
This is the only Classic Sonic boss (rival) fight to have an auto running feature, as if the player does not move the control stick that moves Sonic, he will continue to move at a slow pace that barely keeps him from falling with the disintegrating road.
While facing Metal Sonic, there is a glitch possible when he uses his final attack. Getting hit at a certain point on the screen will cause nearly all of the platforms on the stage to vanish. Sonic will turn around and continue running, with the camera fixed so that he does not always run in the same direction. Despite the glitch, Metal Sonic will continue to attack, and can in fact be beaten. The floor will remain invisible during the cutscene and result screen. The glitch can be removed by pausing and starting over.
In the PC/console version of the battle, Metal Sonic's jet engine emits purple energy streams behind him. However, in the Nintendo 3DS version, the energy streams are blue colored.
Metal Sonic is the only rival boss that was not allied.