By Andrew Gamble & Andrew Gamble Travis Kelce and Patrick Mahomes had a tough time during the Kansas City Chiefs’ Christmas Day match against the Las Vegas Raiders, which ended in a 20-14 defeat for the Chiefs. The game, held at Arrowhead Stadium, saw the Chiefs struggle to find their usual form. The reigning Super Bowl champions have had a challenging season, with this first half against the Raiders being perhaps their worst performance yet. The Chiefs’ offence seemed slow off the mark, while the Raiders, under interim rookie head coach Antonio Pierce, scored defensive touchdowns on back-to-b…