The Radio 1 presenters entered the DJ clash at the PS Vita Rooms in London, which hosted the first in a series of events leading up to its UK launch on February 22.
Moyles's set, which included the likes of The Bee Gees and Nelly, eventually lost out to Westwood in the music battle.
He later tweeted: "Well, @TimWestwood beat me on the decks in #PSVitarooms, but managed to 'borrow' an actual #PSVita. Yeah! A new toy to play with. Top night.
"Had a good night with @PSaccess and thanks for my new #PSVita! The #PSvitarooms is 80 Oxford Street if you wanna pop in. Tell em I sent ya!"
Other celebrities in attendance included grime collective Roll Deep, Goldie and Hollyoaks actors Darren Jeffries and Matt Littler.
Sony recently released its first television adverts for the Vita in the UK and Japan.
> PlayStation Vita: Hands-on with Sony's new handheld
The PlayStation Vita Rooms will be open to the public everyday from today (February 17) until February 22. PlayStation Vita, the next generation console, will be released on February 22.
Watch the trailer for the Playstation Vita below: