The home side continued from where they left after the resounding win over Sher-e-Punjab the previous day to put themselves in the reckoning after a not-too-good showing earlier in the tournament.
Goals by Ravi Pal Singh (8th minute) and Jarnail Singh (36th) put the Lions high in the saddle, before Rajpal Singh pulled a goal back for the Delhi side in the 51st minute.
The Lions, however, were undaunted by the reverse and despite being reduced to 10 men with 20 minutes to go for the hooter, held on.
With four minutes from time, Len Aiyappa, who starred in the victory over Shers the previous night, sealed victory, scoring from a penalty-corner.
Earlier,Bhopal Badshahs made a remarkable comeback to hold second-placed Chandigarh Comets 4-4 in a 11th round match in Bhopal.
Down 0-4 in the first two quarters, Badshahs made a spirited comeback and scored four goals in the next two periods to deny Comets full points.
Expectedly, it was the team from Chandigarh that dominated the first two quarters, pumping in as many as four goals, through Sukhwinder Singh [ Images ] Gabbar (8th and 20th minute), Gurjinder Singh (9th), and Amir Khan [ Images ] (30th).
But Badshahs came out a determined lot in the last two quarters and scored through Affan Yousuf (40th minute), Sameer Dad (47th), Shailendra Singh Bundela (61st, 64th) to force a draw.
By virtue of the draw, Comets consolidated their position in the standings and moved to the second position with 19 points from 11 matches.
The draw also raised Badshahs' semi-final hopes and they now lie in the sixth position with 14 points from 11 games.
Badshahs next host bottom-placed Mumbai [ Images ] Marines, while Chandigarh travel to Chennai to play third-placed Chennai Cheetahs on Monday.