Delray Beach - Injury-nagged 2009 US Open champion Juan Martin Del Potro advanced to the ATP Delray Beach Open semi-finals on Friday by defeating French fifth seed Jeremy Chardy 6-2, 6-3.
In his comeback event after sitting out for nearly a year, the 27-year-old Argentine wildcard entrant earned a Saturday berth against 61st-ranked Sam Querrey, who rallied to dispatch fellow American Tim Smyczek 6-7 (1/7), 7-6 (7/4), 6-4.
Bulgarian fourth seed Grigor Dimitrov will face American Rajeev Ram in the other semi-final. Ram, ranked 89th, won their only prior meeting at Atlanta in 2011.
Del Potro, ranked 1 042nd in the world after missing most of the 2014 and 2015 seasons with a left wrist injury, underwent surgery last June and had not played an ATP match since last March until this week.
The South American standout served well and was effective with his two-handed backhand, attacking 30th-ranked Chardy's second serves and winning 14 of those 22 points over the 80-minute match.
Del Potro also won a 2012 Cincinnati quarter-final from the Frenchman, but Chardy took a five-set triumph in the third round of the 2013 Australian Open.
Del Potro has won both career meetings with Querrey, taking the 2009 Auckland final and a 2011 Valencia quarter-final without dropping a set.
Querrey seeks his eighth career ATP title and the first since Los Angeles in 2012.
Smyczek dominated the first tie-breaker and broke when Querrey served for the second set in the 10th game, only to see his rival jump ahead 5-1 in the second tie-breaker on the way to forcing a third set.
Smyczek squandered four game points in the final game and was broken when he swatted a backhand wide to end the match, ending his hopes of a first-ever ATP semi-final.
World number 28 Dimitrov downed French eighth seed Adrian Mannarino 6-4, 7-5, firing seven aces in windy conditions to dispatch the 2015 Delray semi-finalist in 79 minutes.
"With the windy conditions, the only thing you can do is to stay focused," Dimitrov said.
Dimitrov, who won the most recent of his four career ATP titles in 2014 at Queen's, seeks his second final of the year after falling to Viktor Troicki in last month's Sydney championship match.
"I just want to play a lot of matches and improve my game, Dimitrov said. "Step by step I will get back to the level I want to be at."
Ram rallied to beat Germany's Benjamin Becker 3-6, 6-4, 6-3. Ram seeks a third career ATP crown after winning on Newport grass in 2009 and last year.
Results from the fifth day of the ATP Tour Delray Beach Open on Friday (x denotes seed):
Grigor Dimitrov (BUL x4) bt Adrian Mannarino (FRA x8) 6-4, 7-5
Rajeev Ram (USA) bt Benjamin Becker (GER) 3-6, 6-4, 6-3
Sam Querrey (USA) bt Tim Smyczek (USA) 6-7 (1/7), 7-6 (7/4), 6-4
Juan Martin Del Potro (ARG) bt Jeremy Chardy (FRA x5) 6-2, 6-3