Fernando Alonso and Esteban Ocon finished the second practice session fifth and sixth, while Norris could only manage 12th, four places behind team mate Daniel Ricciardo.
“The Renault, or Alpine, was very fast today,” Norris admitted after the session.
“We had a big gap to Alpine in the last two weekends, this weekend they seem a lot more competitive. So it makes the race or the the chance to get into Q3 a lot more difficult. There’s two more cars we might be racing.
“So it’s exciting, but it makes our life a bit more tricky and a bit closer. So it’s going to be tough.”
Norris said the track conditions are “probably a little bit better than last year”, when the surface had been freshly laid, “but still very tricky. A lot of people making mistakes, myself included.”
Drivers found it took several laps to get the best performance out of their tyres. “It’s not easy to put it all together,” said Norris. “You don’t have like an obvious one lap where the tyres are good, they last two or three laps here.”
Having finished on the podium in the last race at Imola, Norris isn’t sure McLaren will be as quick this weekend.
“It’s different, it’s tricky. The car balance isn’t maybe quite as good as the past few weekends.
“So we definitely have a bit of work to be confident of being in the top 10. Which is important to get into Q3, so it’s a bit tougher than we expected, a bit tougher than we want. But we have overnight to try to make some improvements for qualifying.