Rarely has a north London derby had such implications for the destination of the English Premier League trophy.
When Tottenham hosts Arsenal on Saturday it will be a meeting of second and third with only three points separating.
After both lost Wednesday, a draw between the neighbours could allow Leicester to move further in front in its improbable title challenge when it goes to Watford on Saturday.
Leicester was held by West Bromwich Albion on Tuesday but was celebrating the following night when the three teams below them – Tottenham, Arsenal and Manchester City – all lost.
Arsenal's 2-1 home defeat to Swansea has left Arsene Wenger's side on a three-game losing streak in all competitions for the first time in six years. That first Premier League title since 2004 is looking increasingly hard to secure for Arsene Wenger, even in this most unpredictable season.
"We have to focus on our job and come back reminding ourselves that we have some quality as well," the Arsenal manager said.
Tottenham's 1-0 loss at West Ham on Wednesday punctured the optimism gathering around White Hart Lane that the 55-year wait for the title could be ending. Instead of going top in March for the first time since 1964, Tottenham remains second.
Top-scorer Harry Kane is on a four-game barren run in front of goal but Arsenal will be without injured Petr Cech on Saturday as the goalkeeper recovers from a calf injury.
"One year ago we always spoke about reducing the gap with the top four and now we are second in the table," Tottenham manager Mauricio Pochettino said Thursday. "Who knows what will happen in the future? Now we need to be focused on the present."
The future for Tottenham should be a return to the Champions League, having only competed once in Europe's top competition in 2010-11.
Here is a look at the pick of the other weekend fixtures
Suddenly Manchester United's prospects of returning to the top four are looking far healthier. Buoyed by four successive wins in all competitions, United is now only fifth due to neighbour City having a superior goal difference.
"We are showing passion," United midfielder Ander Herrera said ahead of Sunday's game at West Brom. "We fight to the end. We show when we don't play good we can win. I think that the attitude is very good.
"I am optimistic because we can still fight for everything. We want to be in the top four. We know it's not easy because our opponents are tough, but we are Man United: we have to win."
Swansea head coach Francesco Guidolin remained hospitalized on Thursday after missing his side's victory over Arsenal with a chest infection.
The 60-year-old Italian was referred to a respiratory specialist in London.
"Francesco remains comfortable in hospital and is receiving excellent care and treatment," Swansea said in a statement. "He is making good progress and is in good spirits ... no release date from hospital has been confirmed at present."
The victory at Arsenal, with first-team coach Alan Curtis in charge, moved Swansea six points clear of Saturday's opponent Norwich, which is in the relegation zone.
Chelsea remains unbeaten in the league since Guus Hiddink took charge in December, with the ailing champion rising from the relegation zone to 10th place. Chelsea hosts Stoke on Saturday.
West Ham is without seven senior defenders for the trip to Everton on Saturday, with James Collins the latest casualty with a hamstring injury. Sixth-place West Ham is only a point from the Champions League spots.
After being compressively beaten 3-0 by Liverpool, Man City has an easier match on Saturday with bottom-place Aston Villa visiting the Etihad Stadium.
Newcastle, which is a place above Villa but with an eight-point advantage, hosts Bournemouth. Southampton also faces Sunderland on Saturday, while Liverpool travels to Crystal Palace on Sunday.