Arsene Wenger is unable to explain Arsenal's lack of killer instinct in attack this season.
Indeed, runaway leaders City have plundered an impressive 52 strikes from 17 matches to open up a commanding 11-point advantage over closest challengers United at the top of the table.
Pep Guardiola's men are already 19 points ahead of Arsenal, leaving Wenger to question his team's relatively meagre return in the final third.
"Not quite clinical enough, yes," he told a news conference ahead of Saturday's home game against Newcastle United when questioned about the form of his strikers.
"It's difficult to explain. As we spoke about [Alexis] Sanchez last year, he scored 24, he's on four at the moment. But he is still committed and he works hard."
Of Alexandre Lacazette, a club-record signing from Lyon in the off-season, Wenger said: "I feel if you look at his record, it's quite good. Especially at home. At home his scoring record is really good. Away from home, a bit less.
"But also, do the teams defend better? You could say no, because we create more chances than anybody else. Are the chances of the same quality? I don't know. There is no objective reason to have a verdict on that."
The Gunners have had 64 shots but netted just twice in their last three leagues games, losing 3-1 at home to United and then drawing 1-1 and 0-0 at Southampton and West Ham respectively.
Of the attackers at Wenger's disposal, Lacazette has managed eight goals in 17 league appearances, while Sanchez and Olivier Giroud have four apiece. Danny Welbeck has struck three times in 11 outings, with the boss uncertain of the cause of their collective struggles.
He said: "Is it confidence? Is it the fact that the guys think we have absolutely to score? It's difficult to know. But we have the chances, the quality of our game is there. But it's true that at the moment, we cannot show it up with points."