Norris says he has not been driving like a champion as season returns
The Briton is triple world champion Max Verstappen's closest rival in the standings after 14 of the season's 24 races but still 78 points behind the Red Bull driver.
"After the first half of the season I have not performed at the level of a world champion and it is as simple as that," he told reporters at the Dutch Grand Prix on Thursday.
"At certain times I have, and many races I have done but little things have let me down and I cannot afford that. I know that, and I am not happy with that, but that is because I am passionate and I want to win."
Norris took his first F1 win in Miami in May but has had four second places since then.
Most glaringly, Verstappen started last month's Belgian Grand Prix in 11th place after an engine penalty yet still finished the race and ahead of Norris, who had lined up fourth but ended up fifth.
Australian teammate Oscar Piastri has performed better in the last four races, with a first win in Hungary and two second places.
"There are plenty of things I have looked at, and worked on to come back stronger," said Norris.
"My opportunities have gone away from me at the starts. There have been strong moments, too, but they are always overshadowed by a bad start, a bad turn one, or trying to be too safe and stay out of trouble.
"I need to be perfect to compete against the guys we are competing against, and the smallest weakness or deficit can bite you easily."
Despite his downbeat self-appraisal, Norris said he still felt both championships were in reach.
McLaren are only 42 points behind Red Bull and their car is now possibly the quickest with an upgrade for Zandvoort, Verstappen's home race and one the Dutch driver has won from pole for the past three years.
"I want to be optimistic and say there are still chances," said Norris.
"I know it is a lot and it is going to be a very difficult challenge but knowing how I can perform when things click and go well, then I still want to believe it is possible."
