If you're having a hard time with the Onslaught mode of the new game mode...

Dunno why this was so funny to me lmao.

Add a Soraka with full support items (Censer, Redemption, Warmog's plus a bit of extra health). You get healed more health than you give up from rezzing people, and the Soraka can just suicide to refill her health.

As a support you can also sell your boots for that extra bit of gold to buy Redemption just before the third round. You don't really need the movement speed until later on.