Around 250 matches made it a hectic opening day for the 10th All-Orissa Nalco Open Tennis Tournament at Kalinga Stadium in Bhubaneswar today. Matches involved allmost all the 250-odd competitors in all seven events of the three-day tournament being organised by Bhubaneswar District Tennis Association. Matches, however, were based on best-of-games, instead of best-of-sets. After a chaotic start, the opening-day procedings picked momentum to end with a plethora of matches, under lights. Sourav Das caused the only upset of the day by defeating second seed Kiran Nayak in an under-14 singles match. Earlier, State Agriculture Production Commissioner S P Nanda inaugurated the tournament in the presence of BDTA president Suresh Chandra Mohapatra and other office-bearers of the district body.