In my third match I faced a young guy by the name of John with a Necron army. This was by far the shortest game of 40K i've ever played in a tournament setting.
The deployment was Dawn of War and mission straight kill points.
The battlefield was one I'd not seen before - a printed map with city roads on it and terrain placed on it. It gave the mission a very urban feel.
I won the rolloff and deployed first, right up to the halfway mark of the table with a Trukk of boyz and Ghaz as my one HQ and two troop choices. My opponent was allowed to deploy no closer than 18" away.

To my surprise John measured 18" away from the Trukk and deployed one large unit of necrons with the lord as close as he could and another bunch of necrons off to their flank. I knew that unless he stole the initiative he was going to be in very deep trouble.
Turn 1 Ork
The rest of the ork army entered the board, with the trukk boyz heading towards his lordless necron unit. My nobz moved up the centre.
Ghaz and the boyz pushed forward with their green paint job (red meanz stop, green meanz go!) trukk. Deploying they charged into the Large necron squad with their lord - tearing them apart, breaking them, chasing them down and stomping on their bits.
Turn 1 Necron
The remainder of the Necron force moved onto the table. John pushed up a squad of destroyers to support his remaining necron squad and they shot up the trukk for the nobz. It careened a further 6 inches forward towards the necrons. A unit of immortals moved into position to fire into Ghaz and his squad of boyz at reasonable range, taking a few out.
Turn 2 Ork
With Ghaz calling the Waaaaaaagh! The trukked boyz raced forwarded, disembarked and plouged into the destroyers - wiping them out. The nobz - on foot - managed to close the distance thanks to the extra Fleet move and assaulted the unit of Necron warriors - breaking them and stomping them. Ghaz and boyz caught the immortals and did likewise.
The necrons phased out.
Necrons are vulnerable to hand to hand - but when it comes to Orks it would be a very hard push for them to achieve anything but a massacre.
It's a pity more necron players don't use the scarab swarms, they can effectively tarpit most vehicle mounted troops and allow the necrons to shoot up threats piecemeal.