Arsenal's eight-point lead at the top evaporated in the last two months amid a wretched run of form and Saturday's 1-0 defeat at Nottingham Forest gave City an unassailable lead as they won the title with three games to spare after an incredible run.
Since Pep Guardiola's City lost 1-0 away at Tottenham Hotspur at the start of February, they won 13 of their 14 games and did not lose en route to the title.
"Arsenal pushed us right to the limit, they've been fantastic, so all credit to them. We just went on an incredible run, they had a few hiccups, we capitalised on it and we've managed to end up where we have," Walker told City's website.
"It's the players we've got. We're a bunch of lads who have achieved so much over the last number of years and we understand the standards we've set.
"As for inspiration, there's the captains, managers and so on but we drive ourselves. We achieved so much over the past five or six years, but we knew the bar wasn't high enough at the start of the season."
City also had the psychological edge in the title race after they beat Arsenal twice in that run, scoring four in the second game - a blow Arsenal briefly recovered from before they withered under pressure.
"We wanted to prove anyone doubting us wrong - it wasn't good enough," Walker added.
"It was the first season where we kept on scoring late goals so until the end, we know we can do it.
"The standards of Premier League have gone up, but this is what this club is built for. Certainly that's how it's been for the six years I've been here, so fair play to everyone involved."
