Well being a soldier, he would've had training. But Tidus has great quickness. Being so agile, he would be hard to hit.

In a battle, invovling strength Tidus is fucked, but if Tidus keeps away from Cloud and prepares to attack, he could win. The chances of this are low though.

Cloud would chop him into if he caught up to Tidus. If he didn't and Tidus could keep it a stealth based battle, he would definately win.