A mercy rule final score of 12-2 against a ranked Oklahoma team at Baum-Walker Stadium looked effortless and dominant. Arkansas cranked four homers in seven innings. It looked like a team that had figured something out at exactly the right time. There is a warning attached, though. Razorback fans have been here before. They know better than to count a series as clinched before Saturday's first pitch even crosses the plate. Friday was genuinely impressive for the No. 17 Hogs against the No. 24 Sooners. Arkansas went deep four times, sent nine different players across home plate and chased Oklahoma starter LJ Mercurius after recording just four outs. The final score was 12-2 in seven innings, the kind of result that makes a fan base feel like the postseason rotation is clicking at the right moment. It's the second straight Friday the Hogs have won a series opener by that exact score in that exact number of innings. It's still not a guarantee of anything.…