What if Cleitus had been too slow?

In 334 B.C.E Alexander the Great was disarmed and dismounted before being stunned by a blow to the head. Seeing his forces breaking the Persian satrap tried to bring some good of his defeat and charged the dazed Macedonian. He was already in mid-swing when one of Alexander’s men, a man called Cleitus the Black, leapt to the rescue. He felled the satrap’s arm and saved the king.

My question is: what would have happened if Alexander had been cut down then and there? Had Cleitus been a second too late, the king would’ve died before taking Tyre, Gaugamela, Hydaspes, and spreading Greek influence across the Persian empire.

How do you think this might have sculpted the events of history?