Mercedes had another difficult weekend at Monza, where Ferrari was clearly a step ahead and the W14 was the third-fastest car.
George Russell and Hamilton eventually finished fifth and sixth as they showed an obvious top-speed handicap.
Hamilton's life has been made harder of late by a couple of difficult qualifying sessions, with the seven-time champion starting only 13th at Zandvoort and eighth at Monza.
While on both occasions he has moved up the order and scored decent points, his team has not been leading the chase of pacesetter Red Bull.
"Races are pretty straightforward for me," he said. "I've just got to do better in qualifying, so it's not such a difficult day.
"And just living with the car that we have at the moment. Today is the third fastest car, and it's obviously painful for all of us. We wish we were quicker. But we're just counting down the days until February."
For the second consecutive race Hamilton went for an offset starting tyre strategy in Monza, and he was just one of three drivers to go for the hard compound in his first stint.
After a surprisingly early stop for mediums on lap 27, he was heard to question the decision, as he had expected to stay out for another eight laps.
He also made it clear that he had doubts about getting his mediums to the flag without a further stop, saying at one point: "Now we're screwed, I don't know how these tyres are going to last."
In the end, he managed the tyres and worked his way past Fernando Alonso, Oscar Piastri - with whom he made contact and earned a five-second penalty - Lando Norris and Alex Albon on his way to a top-six finish.
"I definitely wasn't upset," he said when asked about the radio messages. "I was just supposed to go to lap 35, and the pace didn't feel that great at that point. But they stopped me.
"The lap I pitted they said that I was going to target, and then all of a sudden they boxed me. So I was a little bit confused with that, that's all. And then I was definitely concerned that I might not make it to the end.
"The gap was large between myself and the McLarens, I dropped back behind an Aston. So I didn't, at that point, realise what my trajectory might be. But I took care of the tyres, closed the gap, and had that good battle."
