Norris has admitted to not being comfortable with the new McLaren car since the start of the season, despite leading the championship by three points from Piastri coming into the fifth race of the season.
He said he had been concentrating on gaining confidence in the car on the high-speed Jeddah street track.
Norris said: “A pretty decent first day. Always feels chaotic around here because it’s so fast, a lot of walls, a lot of near-misses.
“Today has been a day of working on myself and my driving more than probably working on the car. Getting more confident.
“A good start, productive, gaining confidence, gaining feeling. From what I wanted to learn today, on the right tracks.
“At the minute, I would say we feel confident but the others are not far behind. I was probably hoping we got a bigger gap than we had today. We know we’re fast. We know we have a great car,. Not as comfortable as we would like.”
Piastri said: “The pace in the car is good and I’ve been feeling pretty good. There have been a few corners I try and need to do a better job at tomorrow.”
Although Verstappen was third fastest overall, the Dutchman was lagging behind Ferrari and Mercedes on race pace in both the first and second sessions.
The four-time champion said: “We tried some different things, trying to find maybe a different direction, and we learned a lot from it.
“Still not where I wanted to be. I don’t really look at the gaps, you have to go from what you feel in the car. Over one lap it is a bit better but the long runs were very tough still for us.”
Although Leclerc ended the day 0.482secs slower than Norris, he did not get a clean lap on the fastest soft tyres.
He and Russell appeared the closest thing to a challenge for the McLarens on a race run, but if anything the championship leaders’ advantage appeared bigger than at any race so far this season.
Leclerc said: “A tricky day. It’s a very challenging track where confidence needs to be very high to perform at best.
“We changed a lot on the car but it was a very positive day because I have learned a lot from it and I think once we put everything in the right window there should be a bit more performance coming from the car.
“But McLaren seems to be very strong, a lot stronger than us but never say never. If you put everything together everything is possible.”
