In a game in which fortunes fluctuated wildly, Mumbai took the lead and then conceded three goals to be 1-3 down at the halfway stage, before storming their way back with some superb play in the third quarter to move up 4-3.
But Delhi's superior passing skills and timely interceptions helped the visitors pump in three quick goals in the initial stages of the fourth quarter to quell Mumbai's hopes of breaking their losing streak in the five-team league.
The defeat was Mumbai's fourth straight, and second in as many days at home, but the margin of loss ensured they picked up one more point to take the tally to four.
Delhi, with their third win in four games, shot to the top with a tally of 17, five ahead of Uttar Pradesh Wizards who have played one fewer game.
Delhi's goal-getters in the high-scoring match were Oskar Deecke, Norris Jones Lloyd, Danish Mujtaba, Akashdeep Singh, Andreas Mir Bel and Simon Child.
For Mumbai, their penalty corner expert Sandeep Singh scored twice off set-pieces, while the other two goals were notched by Glenn Turner and Jason Wilson.
Mumbai, beaten 2-1 by Delhi in their previous encounter in the latter's backyard, started the return game with a narrow escape when Akashdeep Singh's deflection from a fine right centre by Gurvinder Chandi went wide of the far post.
Mumbai took the lead against the run of play through their penalty corner ace Sandeep Singh who sounded the board nonchalantly off their first award in the eighth minute.
Stung to the quick, Delhi hit back six minutes later when a fine pass by Akashdeep from the top of the D went to an unmarked Deecke, who struck home past the hapless home team custodian P T Rao.
