Indian Greco-roman grapplers failed to impress on the opening day of the World Olympic Games Qualifiers, bowing out in preliminary rounds in all six weight categories in Istanbul on Thursday. (More Wrestling News)

Sumit (60kg), Ashu (67kg), Vikas (77kg), Sunil Kumar (87kg), Nitesh (97kg) and Naveen (130kg) lost their bouts, with the focus now shifting to freestyle.

Sumit lost his 60kg opening-round bout to Romanian opponent Razvan Arnaut on technical superiority 10-0, while in 67kg, Ashu overcame his Norwegian rival Haavard Joergensen 5-4, before losing 10-0 on technical superiority to seventh-ranked Hungarian Krisztina Vancza.

In 77kg category, Vikas got the better of Riccardo Abbrescia of Italy before going down in the pre-quarterfinal bout to Georgia's Luri Lomadze 8-0 on technical superiority.

Lomadze jumped out to a big lead using an arm throw for two points. He then got behind Vikas to nail a four-point throw. Lomadze then effected a takedown that ended the contest with 25 seconds to spare in the first period.

In the 87kg category, Sunil Kumar overcame the challenge from Jose Andres Vargas 3-1 before losing to Azerbaijan's Rafig Huseynov 4-3 in the pre-quarters.

In fact, Olympic bronze medallist Rafig advanced to the quarterfinals by the slimmest of margins, overcoming a 3-1 deficit in the final seconds for an improbable win.

With time running out, Rafig got in on a body lock and forced Kumar over the edge for a step-out. But the Indian was assessed a one-point penalty for fleeing, giving Rafig a 3-3 win on criteria. An unsuccessful challenge added the final point.

In the 97kg category, Nitesh got eliminated in the qualification round itself, losing to Poland's Tadeusz Michalik, who effected a victory by fall.

Naveen, in 130kg category, too bowed out in the qualification round losing to Austria's Daniel Gastl on points.