SAN FRANCISCO — Josuar Gonzalez and Luis Hernández might be a long way from making their major league debuts, but if their first professional game together in front of a paid crowd was any indication, the two highly touted teenage infielders already know how to entertain a packed house.Newly promoted from the Arizona Complex League to Low-A San Jose, the Giants’ two top prospects took turns showing off their defensive skills, eliciting cheers and a gasp of disbelief or two from the crowd at Excite Ballpark Saturday night.Gonzalez’s debut was all too short, though. He exited in the fifth inning as a precaution because of a groin cramp that interrupted his third at-bat of the game. Prior to that, the 18-year-old switch-hitting shortstop and leadoff hitter was having an eventful evening. He singled in his first at-bat (109 mph exit velocity), stole a base, drew a walk and made a diving catch of a knuckling line drive. Gonzalez also made two outs on the bases, thrown out by 10 feet when he tried to take third base on a ball that got past Ontario catcher Conner O’Neal in the first inning, then thrown out trying to steal second base in the third on an apparent blown call.Hernández went 0-for-2 with a sacrifice fly, demonstrated zone awareness while drawing two walks, and made the play of the night, ranging far into foul ground after gloving a ground ball that threaded the chalk line. He showed off his arm strength while heaving a 140-foot jump throw that arrived at first base without a bounce. It was the type of play only a handful of major league third basemen could make. It’s hard to imagine five-time Gold Glove winner Matt Chapman could’ve done it any better.