Arsenal's Norwegian midfielder #08 Martin Odegaard during the English Premier League football match between Leeds United and Arsenal at Elland Road in Leeds, northern England. AFP
The Gunners' advantage over Manchester City and Aston Villa, who are both in action on Sunday, stretches to seven points as Mikel Arteta's men took another step towards the title at Elland Road.
A first home defeat of the season last weekend to Manchester United capped a run of just two points from a possible nine in Arsenal's previous three league games.
After finishing runners-up for the past three seasons, questions were raised over the mentality of Arteta's men and their ability to get over the line in a title race.
Madueke's cross was headed in by Martin Zubimendi to open the scoring.
Leeds goalkeeper Karl Darlow could then only parry another dangerous delivery from the England winger into his own goal before half-time.
Despite a fine run of form, Leeds remain only six points above the relegation zone.
Their first defeat at home since November was confirmed when the much-criticised Viktor Gyokeres latched onto Gabriel Martinelli's cross to blast in his 11th goal since joining Arsenal from Sporting Lisbon.
Gabriel Jesus came off the bench to round off the scoring with a blistering strike four minutes from time.
Arsenal will be hoping local rivals Tottenham can do them a favour when City visit north London, while Villa host Brentford on Sunday.
Chelsea's fine start under Liam Rosenior continued but they climbed into the top four the hard way after being outplayed by relegation-threatened West Ham for 45 minutes at Stamford Bridge.
The Blues were booed off at half-time by their own fans after goals from Jarrod Bowen and Crysencio Summerville gave the visitors a deserved lead.
A third consecutive league win would have taken Nuno Espirito Santo's side to within two points of safety.
But they wilted under the weight of Chelsea pressure after Rosenior's triple half-time substitution inspired a transformed second-half performance.
Two of those introduced at the break, Joao Pedro and Marc Cucurella, brought Chelsea level before Enzo Fernandez fired in the winner in stoppage time.
Chelsea move above Manchester United into fourth and open up a four-point lead over Liverpool, who host Newcastle later, in the battle for a place in next season's Champions League.
Everton snatched a 1-1 draw at Brighton thanks to Beto's 97th-minute equaliser in a result that does little for either side's aspirations of European football next season.
Pascal Gross' first goal since returning to the Seagulls from Borussia Dortmund put Brighton in front.
Bournemouth ended any remaining worries of being dragged into a relegation fight as goals from Eli Kroupi and Alex Scott earned a 2-0 win at bottom-of-the-table Wolves.
The Cherries climb up to 12th and 13 points clear of the relegation zone.
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