There is an audio interview on the FFT website:
He says he played a good match, he's happy about his performance today. He wasn't broken once, which doesn't happen so often (he laughes when he says that).
He didn't know at all what to expect today. Olejniczak is... massive (and he laughes again). He was serving very hard. The break in the 1st set was a bit lucky, but from the middle of the 2nd set on, he was able to read his serve and he got his measure.
He feels well on every surface anyway, he needs to get his bearings on grass, so it was important to have an easy first round, but he's able to play well on that surface too.
Next round: another "massive" guy with Calleri. He jokes about the fact that he's playing hulking guys lately since Groth (the Australian he played last week in Nottingham) was quite a hefty fellow too.
Calleri is better on quick surfaces than on clay in his opinion because he's very powerful and doesn't move so well. It's a winnable match for him if he manages to read his serve like he did today.