The technical bench disallowed a Mumbai equaliser in the dying minutes which took Delhi to 13 points.
Penalty-corner specialist Sandeep Singh's 16 goals in six matches have powered Indian hockey back into the Olympics.
The men take on France in the qualifying final, with the winner to go through to the 2012 London Olympics.
The women's team is on the cusp of a first Olympic qualification while the men are looking good for a return after missing in 2008.
India coach Michael Nobbs termed his team's comprehensive 6-2 win over France as "clinical and almost perfect."
India have now scored a mammoth 29 goals in 3 matches in the Olympic qualifiers and top the table with 9 points.
The hockey Olympic qualifiers aren't attracting as many eyeballs as was expected.
Former hockey Olympian Jagbir Singh was impressed with India's 8-1 win over Italy, though he feels the defence is still a cause for worry.
Sandeep Singh has already scored four goals in India's two victories so far.
India registered their second consecutive big win of the Olympic qualifiers as they hammered Italy 8-1.
India beat Canada comprehensively 4-1 in their second Olympic qualifier on Sunday.
India are now level with Italy in second place with four points from two games in the Olympic hockey qualifiers.
Michael Nobbs was unimpressed with the team's 15-1 win over Singapore on Saturday.
India were denied a goal in the 55th minute and a penalty corner in the dying moments on Saturday.
Gurwinder Singh Chandi scored a hat-trick while Shivender Singh, SV Sunil and Danish Mujtaba scored a brace each.
India came from behind through Soundarya to salvage a point in their first match of the Olympic hockey qualifiers.
It's time to right the wrongs by bagging qualification for the London Olympics.
The qualification tournament for London 2012 begins at the Major Dhyan Chand National Stadium from February 18.
Charlesworth was the technical adviser when India failed to qualify for the 2008 Beijing Olympics.
The main turf of the Major Dhyan Chand National Stadium was re-laid before the World Cup in 2010.