Pumped up by four gold medals in kabaddi, three each in archery and athletics and one each from cycling and gymnastics, they amassed 17 gold after Day 4 to catapult from Number 6 to Number 1.
Maharashtra picked up only four gold to manage a tally of 16 to slip to the second position. They have a total of 71 medals, though, as opposed to Haryana's 47, to set up a thrilling race to the finish.
The defending champions, Maharashtra, were well served by Aditee Ajit Dandekar (Girls Under-21 Individual all-Around rhythmic gymnastics) and their 4x100m relay quartet but they could only watch as Haryana went for the kill across sports.
Haryana dominated kabaddi but were surprisingly taken to the wire by Himachal Pradesh in the Girls Under-21 final; the hill state, in fact, rallied from a six-point deficit at half-time to tie the score at 27-27 at the end of regulation time.
Last year's runners-up Haryana had to dig deep into the reserves of their strength and experience to sneak home in extra time.
Meanwhile, Tamil Nadu stole the limelight in athletics, with an equally impressive five-gold show; Kerala's Ancy Sojan too made an impact, anchoring her state's Under-21 4x100m relay squad to collect her third gold medal.
Three of Tamil Nadu's gold medals came in jumps, through S Saran (Boys Under-21 long jump), Pavithra (Girls Under-21 pole vault) and Babisha (Girls Under-21 triple jump). Their gold tally has swelled to seven from track and field, taking them to the fifth place with 8 gold out of 25 medals. Delhi and Gujarat occupied the third and fourth spots.
Haryana dominated archery too, winning 7 medals including 3 gold. Himani Kumari, who missed out on a medal in Pune last year, claimed the Girls Under-21 title with an easy win in the final. Tisha Punia, a quarterfinalist last time, beat her team-mate Tamanna in the Under-17 final while Ridhi took the bronze to ensure a sweep for them in this category.
Madhya Pradesh's compound archers Muskan Kirar (Girls Under-21) and Chirag Vidyarthi (Boys Under-17) bettered their last year's performances to bag gold medals this time. Chirag Vidyarthi had to hold his nerve in securing a 1-point win against Rajasthan's Rajesh Bishnoi.
Haryana cyclist Anil Manglaw secured the most comfortable victory in the road races held on Monday. Assam's Gongutri Bordoloi won the Girls Under-21 road race (60km) in a stirring finish that saw the podium finishers separated only by 0.15 seconds. Similarly, Delhi's Arshad Farid and Maharashtra's Pooja Danole outsprinted their rivals in the Under-17 races but only just.
Gujarat's Rushiraj Jadeja, a student of the District Level Sports School in Ahmedabad, finished sixth in qualification but came into his own to win the Boys Under-21 10m Air Rifle gold from home favourite Hridhay Hazarika.
Parth Makhija (Delhi), who topped qualifying with 630.6 finished fifth, three sub-10 shots hurting him.
Rudraksh Patil (Maharashtra) took the other gold on offer in the shooting ranges on Monday, the 10m Air Rifle for Boys Under-17 with a consistent showing both in qualifying (627.2 points) and in the final where he beat Keval Prajapati (Gujarat) quite comfortably.
Gujarat's judokas showed their growing prowess on the mat to win three of the eight gold medals on offer in the Under-21 competition. Seven of the state's 10 gold medals have come from the Judo competition. While Gujarat's sustained efforts to rake in medals hogged the limelight, Mizoram's Chinglinmawaii caught attention by winning the Girls Under-21 52kg class for her state's second gold in all.
( With inputs from IANS )