By Doug Vazquez,SI Betting Staff Best bets and analysis for Saturday’s UFC Fight Night card, headlined by betting favorite Aleksander Rakić facing Jan Blachowicz. Former light heavyweight champion and No. 1 contender Jan Blachowicz steps into the Octagon as the underdog at SI Sportsbook (+155) against an extremely dangerous opponent in Alexsandar Rakić. The third-ranked contender did not earn his ranking or his heavy favorite status (-188) without reason. He is 3-1 in his last four fights, with convincing decisions over division veterans Anthony Smith and Volkan Oezdemir. Blachowicz, a grizzle…