DELRAY BEACH, Fla. (AP) Juan Martin del Potro is inching ever closer to the level of the top-five player he was three years ago.

The Argentine player reached his first ATP semifinal in more than two years, beating fifth-seeded Jeremy Chardy of France 6-2, 6-3 on Friday night in the Delray Beach Open.

Del Potro, once ranked No. 4 in the world but now No. 1,041 because of an 11-month layoff following two surgeries on his left wrist last year, will play unseeded American Sam Querrey in the semifinals.

In a sign of his growing confidence, del Potro relied more heavily on his two-handed backhand rather than the more dependable one-handed slice he used in his first two matches. Though admittedly fatigued, the 27-year-old Argentine dominated the court, moving fluidly and setting up his hallmark forehand down-the-line winners.

''He put me on the defensive and against these top 30 players you cannot use slice all the time,'' said del Potro, who also admitted to feeling less jittery than he did in his previous matches. ''I actually prefer to feel nervous to how I feel right now which is just tired.''

Querrey squeaked past wild-card Tim Smyczek 6-7 (1), 7-6 (4), 6-4 in 2 hours, 29 minutes, denying the 28-year-old Wisconsin player his first career tour-level semifinal. Smyczek was one game away, leading 6-5 in the second set before Querrey won the tiebreaker and then broke in the final game of the match.

American Rajeev Ram saved five break points in the crucial eighth game of the second set and beat Germany's Benjamin Becker 3-6, 6-4, 6-3 in windy conditions in another quarterfinal.

The 31-year-old Ram will face fourth-seeded Grigor Dimitrov of Bulgaria in the semifinals. The 24-year-old Dimitrov beat eighth-seeded Adrian Mannarino of France 6-4, 7-5.

Ram had two double faults in the whippy wind to give Becker break chances at 4-4 in the second set. But the 6-foor-4 Ram erased one with an ace and held with a service winner.

So difficult were the conditions that, in the third game of the third set, Ram hit a serve that Becker returned deep of the baseline. But, as Ram tried to jump out of the way, the ball hit his foot, awarding the point to Becker.

Ram was also bolstered by the pro-American crowd which clapped between serves and continually called out ''Ram it'', much to the dismay of chair umpire Zsolt Beda. After repeatedly attempting to calm the throng, the Hungarian official finally implored, ''Thank you ladies and gentleman, we get the joke.''

Ram admitted later that the comment made him laugh out loud.

Dimitrov broke Mannarino in the final game of both sets to reach his second ATP semifinal of the year. In January, Dimitrov lost to Victor Troicki in the final of the ATP event in Sydney.

''It was so swirly out there that I only practiced for 20 minutes,'' said Dimitrov of the wind that has wreaked havoc all week. ''You just have to stay focused and get the job done.''