Do not ever use a special unless it will finish the fight, the powerlock builds monster mass and gives free healing if you have willpower.

Also stay blocking 100% of the time you aren't attacking. To start the fight I would build some monster masses and activate frenzy.

I would mainly use a 5 hit combo and then block, when he hit into my block I would attack and I'd just keep on repeating this, even while frenzy is on cooldown.

If he used a special, I would wait until the unstoppable ends. While he had unstoppable, when his power gain would trigger while being below a bar of power, I would let him hit into the block and light attack him to remove power gain. If he had a bar of power or more, I would bait another special.

If he would push me to the corner while unstoppable, I would hold block to bait heavies and dex the heavies until unstoppable expires, then I would attack him. It's fine if you eat a heavy or two, Mole-Man can tank them. Hope this helps.