GIANCARLO NAVACH and DANILO MASONI SHARES in English soccer team Manchester United and Italy's Juventus jumped on yesterday after they and 10 other top European clubs announced the formation of a breakaway Super League that could significantly boost revenue for the clubs' wealthy owners. Juventus' share price surged nearly 19% as shareholders cheered the move to set up a rival to UEFA's established Champions League, Europe's most prestigious club competition. Shares in Manchester United rose 9% after opening on the New York Stock Exchange. The Super League, financed by U.S. bank JP Morgan, heralds the prospect of bigger and more…