The Ferrari driver's strong run of seven consecutive front-row starting positions ended in Australia where he qualified fifth before a penalty for Sergio Perez gifted him a place.
He struggled again at Suzuka, where he couldn't better eighth after having to use a second set of tyres to guarantee safe passage out of Q1.
In both races, he came through the field to take second and fourth positions respectively, but he insists that he needs to start further up the grid.
"If I only look today I'm very happy, I don't think there was anything we could have done better," he said when asked by Motorsport.com about his Suzuka race.
"The pace was really good, tyre management was really good, communication was really good.
"However, as a driver, you always have to look at the negative over the whole weekend.
"And whether it's in Australia or here, race pace has not been a problem - it's my qualifying pace, which is not something that I've been very used to in my career, to be working on my qualifying pace, because normally it's pretty good on the Saturday.
"However, since two races now in a row, I've been struggling to put the tyres in the right window.
"And this is definitely my main focus now going into Shanghai, to try and refine the right window, the tyres, and for me to put them more consistently inside that window. Then once I'll do that, I'm sure the pace will come back in quali."
Leclerc insisted that his current struggle is all about tyre preparation.
"One hundred per cent," he said. "Because as I said, my laps weren't that bad. Yesterday, the lap I have done was actually really good. But the grip that was available from the tyre was just not there.
"And this is because I do a bad job on the lap before, which is very frustrating, because you finish a lap and you're happy. But actually you're nowhere.
"So I've got to focus on that. It's very fine, like very little differences. However, I'm confident that by analysing well the data – we've got a week before Shanghai – and whenever I focused on something, I improved quite quickly on it. So I'm not too concerned.
"But I need to do this step forward for Shanghai now."
Ferrari team principal Fred Vasseur downplayed Leclerc's concerns, pointing out that his Suzuka session was compromised by Q1.
"You don't have to draw a conclusion just based on the classification," said the Frenchman. "I think where we missed a little bit the weekend with Charles yesterday was the first lap of Q1. He didn't do a mega lap, and we had to put the second set on, because we were a little bit at risk.
"And then you go to Q3, you have only one set. And you are a little bit on the back foot, because you're like, 'If I do a mistake, I will be P10'. And we didn't take the right approach on qualifying.
"But now I'm convinced that Charles is a competitor, he is the good one on one lap qualifying, and it will be back soon.
Pressed on Leclerc's own admission that he needs to improve, Vasseur added: "Yeah, he's lucid on the fact that he didn't do a good quali yesterday, and you can't be happy when your team-mate is P4, and you are P8.
"But overall, we need also to have a deep look on quali, on the session. We missed the Q1, and then we landed at the end only with one set in Q3, and if you finish one-tenth off the second row it's not a disaster as if you are six-tenths off on that.
"And it will be another one next week, we'll have two qualis in China, two opportunities to do the job."
