This time last month Arsenal were seemingly in the fast lane to their first Premier League title in 22 years, with a stuttering Manchester City leaking points and losing ground.
On Sunday, however, a rejuvenated City will know that victory over the north London club in a showdown at the Etihad Stadium would make them favourites to reclaim the crown.
Arsenal's surprise 2-1 home defeat by Bournemouth last weekend re-opened the race and City's subsequent 3-0 win at Chelsea cut the gap to six points with a game in hand.
If City prevail and then win at relegation-bound Burnley three days later they would top the table with five games to go and leave Arsenal facing the unedifying prospect of a fourth successive runners-up spot.
Should that happen it would be a crushing blow for Arsenal manager Mikel Arteta, whose desperation to deliver the title appears to be weighing heavily on his players.
"You're going for your first title, you start to become consumed, and it's the mental and emotional drain that means your legs physically appear tired," former Manchester United defender and Sky Sports pundit Gary Neville said.
"This is where it gets real. This is the title race now, and they (Arsenal) have got to clear their minds somehow and get that emotional balance correct."
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While Arsenal are still very much masters of their own fate with even a draw at City an acceptable outcome, they will need no reminder of what happened three years ago.
On that April day, Arsenal arrived at the Etihad Stadium as Premier League leaders five points ahead of City, albeit having played two games more.
But City tore them apart in a 4-1 victory that crushed Arsenal's spirit and propelled Guardiola's side to a third successive league title by five points.
CITY AT THEIR BEST IN APRIL
There is something about April that brings out the best in City under Guardiola.
Since a loss to Leeds United in April 2021, they have won 20 of their 22 Premier League games in the month, drawing two.
After a season of inconsistency and dropped points, City are again clicking at just the right time with last month's statement 2-0 League Cup final victory over Arsenal followed by a 4-0 FA Cup rout of Liverpool and the hammering of Chelsea.
While City have not lost at home to Arsenal in the league for 11 years, they know they have zero margin for error on Sunday in what Guardiola describes as 'a final'.
"If they beat us it's over," the Spaniard, who has guided City to six Premier League titles in nine seasons, said.
Arsenal will be buoyed by their 1-0 aggregate win over Sporting in the Champions League quarterfinals on Wednesday.
They are also unbeaten in their last five Premier League games against City and have players who are capable of delivering a knockout blow.
They must free themselves of the nerves that strangled them against Bournemouth, though, or it could be a long afternoon.
Elsewhere in the Premier League this weekend, the stakes are equally high for Arsenal's north London rivals Tottenham Hotspur, although for very different reasons.
With no wins in their last 14 league games, Spurs are third-from-bottom, two points below 17th-placed West Ham United, and in danger of relegation for the first time since 1977.
Defeat for new manager Roberto De Zerbi's side by his old club Brighton & Hove Albion on Saturday could leave them adrift with five games left if Nottingham Forest and West Ham beat Burnley and Crystal Palace respectively on Sunday and Monday.