O'Brien brothers complete treble with Rockfish Donnacha and Joseph O'Brien teamed up for a treble at Gowran Park tonight when Rockfish claimed the nine-furlong handicap. The 5/2 favourite was produced to challenge front-runner Just Sherry on the outer a furlong-and-a-half from home. He got on top inside the final furlong to record a hard-fought half-length win over that rival. The winner was following up his success at Cork 11 days ago and was recording his third career victory having also scored at Dundalk last month. “He got 9lb the last day but he's competitive in that grade,” said Joseph O'Brien. “He's a grand horse and he's after winning his few races. Any horse that wins three races is good. “He's going to go juvenile hurdling eventually. He might get a bit further as he got to the line well.”