The Reds are eight points clear of Leicester City and 11 ahead of the Sky Blues.
Per Goal's James Westwood, Walker said:
"The opposition are probably working us out a bit. Or the opposition are getting better. We are still the same squad.
"We have changed very little. We are still adopting a professional mentality around the place.
"We have to take our hats off to Liverpool. They have been fantastic, and credit where it is due. They deserve to be top, but it is not over until it is over."
Both teams had difficult afternoons on Saturday as City faced Newcastle United and Liverpool hosted Brighton & Hove Albion, but the Reds extended their lead at the summit of the English top flight.
City out-shot Newcastle 24 to six, but the Magpies twice came from behind to earn a 2-2 draw at St. James' Park:
It is not the first time this year that Newcastle have claimed a positive result at home to City, as football journalist Richard Jolly observed:
Pep Guardiola's side have already failed to win five matches this season. In the entirety of last campaign, they only failed to win six times, and they were nine points better off at this stage.
The Reds are unbeaten and were at this point last season, but they're four points better off having won 13 of 14 games.
They looked to be cruising against Brighton after Virgil van Dijk's brace put them 2-0 up after 24 minutes.
Liverpool endured a tense finish, though, when goalkeeper Alisson was sent off for handling the ball outside the area, and Lewis Dunk converted the resulting free-kick with 11 minutes of normal remaining.
Football writer Leanne Prescott hailed the Reds' ability to keep their winning run going despite the circumstances:
Leanne Prescott @_lfcleanne
No doubt the personnel of this team are incredible but their unrelenting, collective ability to grind out wins when they aren’t at their best is phenomenal. Sets them apart from #LFC sides of old. 40pts going into December. Hodgson’s relegation tales are very much in the past.
In terms of performance, Jurgen Klopp's side haven't hit the heights they're capable of this season. They've shipped seven more goals than they had at this point in the last campaign, and they've kept just two clean sheets.
However, their resilience in the face of setbacks has separated them from City and allowed them to open up the considerable gap between them.
City have shown in recent years they're capable of putting together some incredible runs—they won each of their final 14 league games last season—but even if they do something similar again, Liverpool's refusal to drop points could prevent them from making up that ground.