Rupinder created a lot of opportunities and was solid as a defender but it was Lloyd Norris-Jones (26 minutes) and Akashdeep Singh (53rd), who emerged as the goalscorers as Delhi took a big step towards qualifying for the play-offs, taking their overall points to 22.
Delhi looked a confident side right from the start as they played great hockey but could not break the Ranchi defence.
Ranchi Rays, who were placed second in the table, started the third quarter on a positive note but Delhi still dominated the circle penetration. The hosts earned a penalty corner but Rupinder Pal Singh once again squandered the chance, his 10th of the match.
Ranchi got a penalty corner but Ashley Jackson, joint highest scorer of this edition, couldn't convert it. Delhi earned another penalty corner but Ranchi's goalkeeper was upto the task as he staved off a double strike from the hosts.
"Day by day we are improving. We combined well today and I hope we will do well in the next game. We need to communicate more, we have good experienced player," skipper Sardar Singh said after the match.
Rupinder Pal Singh, who was awarded the Man of the Match, said: "We need to work on defence. We planned to do man to man marking. I hope in the next game I score. I have to work more on my game.