Wrestle vs Chain Saw

[Smurf]

Falling down with a chain saw invokes an armour roll.

Will Wrestle do the same?

[Darkson]

Falling down with a chain saw invokes an armour roll.

You don't "Fall Down", it's if you're "Knocked Down" that invokes an armour roll.

Wrestle means you are "Placed Prone" - completely different.

[Vanguard]

Wrestle only comes in to play when a Both Down result is selected. Blocking with a chainsaw does not involve rolling block dice, so this is never an option.
However, if a Wrestle player blocks a Chainsaw player, then block dice are used as normal and could result in a Both Down result. If Wrestle is used then the players are 'Placed Prone' rather than 'Knocked Down', no armour rolls are made and so the +3 from the Chainsaw never comes in to play.
As an aside, if Both Down result is used without Wrestle (or Block), both players would be knocked down and both would suffer +3 to the armour roll. A spectacularly messy, but crowd-pleasing, result.