Speaking after the show, Penk said: "It seemed to go fine and flowed along - but the technical side of the studio is completely different from the studio I am used to.
Evans, 35, had said Penk's age - 39 - would put off the younger audience.
"It's nonsense," said Penk, "I don't think age matters and some of the most successful jocks are in their 40s and 50s.
"Look at Chris Tarrant, Terry Wogan and Jonathan Ross - age doesn't come into it and really doesn't matter.
"Either you can do it or you can't."
Evans' contract was terminated last week when he failed to turn up for work for several days after being photographed drinking with friends and his new wife Billie.
Early starts
Penk - famous for his on-air spoofs - was brought in from rival station Capital Radio and was due to head the drive time show until last Thursday, when Evans and Virgin agreed to part.
Starting his first show with Have a Nice Day by the Stereophonics, he admitted he was not looking forward to the early starts for the 6am programme.
Speaking after the show, Penk said: "It seemed to go fine and flowed along - but the technical side of the studio is completely different from the studio I am used to.
Penk has previously presented TV Nightmares and worked on Capital Radio.
Chris Evans had been Virgin's biggest name DJ, pulling in around 1.75 million listeners.
It is not the first time that Evans has left a radio station under a cloud.
In January 1997 he left Radio 1 after disagreements with station controller Matthew Bannister, and refused to go back into the studio to serve his notice.