Juan Martin Del Potro's comeback from an injury layoff of nearly a year ended in defeat Saturday as the 2009 US Open champion fell to Sam Querrey 7-5, 7-5 in the ATP Delray Beach Open semi-finals. Querrey fired 10 aces and won 30 of 34 points on his first serve to advance after 80 minutes without ever facing a break point, booking a date in Sunday's final against fellow American Rajeev Ram, who upset Bulgarian fourth seed Grigor Dimitrov 6-4, 6-3. Del Potro, ranked 1,042nd in the world, was in his first event since last March following left wrist surgery last June. The 27-year-old wildcard entrant missed most of the 2014 and 2015 seasons due to the wrist.