The 18-year-old rookie had a shaky start to pre-season in the opening Barcelona test - including two spins and a crash that cost Williams a full day of running - before a smooth second week of running at the Spanish track.
While Stroll, the son of Canadian billionaire Lawrence, is seen by some as a 'pay driver', the teenager says he is not fussed by the criticism.
"I don't care about the critics. It's none of my business," Stroll said.
"We're all professionals. Things happen in motorsports and you've just got to bounce back from it.
"It's all pretty straightforward to everyone. It was a frustrating [first] week but we set our minds on [test two] and did a good job.
"We got all our running in: long runs, short runs, all compounds of tyres, so it was a good week.
"I was going to do a 1m19.5s before I went off. I was eight tenths up on that lap on the ultra-softs.
"I think it's quite OK but it's not the time to be focused on lap times."
Read the full article on eurosport.co.uk: Stroll: I don't care about critics