But after feeling unwell and dizzy when he got out of the auto, Massa cancelled his post-session media activities and went to the medical centre at the track to see doctors.
"Williams supports Felipe's decision and the team will work with him to ensure he makes a full recovery, with a view to return to the race track for the Belgian Grand Prix".
Massa, 36, had been given the all-clear by the FIA to continue his participation here on Saturday morning after he was taken to hospital following complaints of dizziness.
To compound this, di Resta came into the crucial session having only driven 10 laps in an F1 vehicle since the end of 2013, when he last raced in F1.
For the 31-year-old Di Resta, it is an unexpected chance to get back behind the wheel in F1.More news: Uttar Pradesh: Two SP MLCs, one BSP MLC resign from Legislative Council
More news: First human gene embryo editing could stop genetic diseases
More news: Eight Bodies Discovered In a Texas Truck In 'Ruthless' Human Trafficking Incident
"You're very anxious. Nervous but very excited".
Williams has confirmed Di Resta will carry the number 40 on his auto, which is the team's designated reserve driver number.
"I have just sat with Paul di Resta while he was trying to have some lunch". You go straight in the deep end.
"I'm sure there are some nerves there, he hasn't had much time to get ready, but I have utter confidence in him that if anyone can do this, Paul can". You just have to get in the auto and do the job possible.
"I think he's more upset than anything else", Williams told Sky Sports on Massa's situation.
Nevertheless, despite getting only 11 laps in Q1 di Resta steadily built up his pace, achieving his first objective to get well within the 107 per cent qualifying time before then even picking up a spot at the expense of Marcus Ericsson to qualify 19th.