There were 922 wrestlers that stepped onto the mats at the ASICS/Vaughan Junior  Greco-Roman Championships on Sunday evening, but it was the five returning champions who made the big splashes.    Returning champions Gabriel Mooney (Minnesota), Brock Zollinger (Idaho), Sam Hazewinkel (Florida), Trent Paulson (Iowa) and Matt Herrington (New York) all completed first-day competition undefeated. The five wrestlers outscored their opponents by a combined score of 72-5.    Mooney, the only returning champion on the ASICS Tiger High School All-American Team, won his only match of the day 10-0. Only a sophomore, Mooney was a double-champion last year at this event. He is competing at 105 lbs.    At 112 lbs., Zollinger was the only returning champion not to record a technical superiority, winning his lone match 11-4.    Hazewinkel won by technical superiority 10-0 at 119 lbs. to move on to the second day of competition. Hazewinkel, who slightly injured his ankle at the Junior National Duals three weeks ago, was in the Junior National finals last year in both styles, but was only able to come away with a Greco-Roman title.    "I really want to win both styles," said Hazewinkel, who will compete at the Univ. of Oklahoma next year. "That is my main focus for this year - being a double-champion. If I can do that, I can end my high school career as a happy man."     At 152 lbs., Paulson is wrestling up from his high school weight of 145, but does not appear to show signs of struggle at the upper weight. Paulson won both of his matches by 10-0 scores to move on to day 2 completely rested.    Paulson's twin brother, Travis, won by scores of 11-0 and 5-0. Travis, competing in Pool A, is on a collision course to meet up with Trent in the finals, who is in Pool B.    "It would be cool if me and my brother met in the finals," Trent said. "I am not sure yet if we would wrestle or go as co-champions, but it would be a big honor and great for the state of Iowa if we could both make it."    Herrington, who holds the national high school record for career victories, won both of his matches at 171 lbs. on Sunday evening. His 11-1 and 10-0 wins moved him to day 2  unscathed.    Preliminary Round 2 of the ASICS/Vaughan Junior National Greco-Roman Championships will begin at 9 am (Central Time). For complete coverage,   continue to logon to TheMat.com.