Flavia Pennetta has reached her first Grand Slam final with victory over Simona Halep in the first of the delayed women's US Open semi-finals.

The Italian broke the world number two twice in the first set and four times in the second as she secured a 6-1 6-3 victory in just under an hour.

Pennetta lost to Victoria Azarenka at this stage of the competition two years ago but started the match in frantic fashion as she looked to go one better, surviving a break point at 1-1 before taking her own in the very next game to establish a 3-1 first-set lead.

The Italian broke the world number two again as Halep caved, and when the Romanian gave up her serve again in the very first game of the second set it looked as if she would offer no resistance.

Things improved, though, as Halep secured a first break of her own when she started to get her opponent scrambling around the court for the first time, and she looked to have marked a turnaround in fortunes as a second break gave her an advantage of 3-1 in the second set.

However, Pennetta responded immediately with a break back as Halep's serve crumbled and after matching a drop-shot with an even better one of her own, she smashed a forehand winner down the line to break again and move 4-3 ahead.

The 33-year-old made it 15 points in a row to move within one game and broke Halep's service at 5-3 to secure victory and a final showdown against Serena Williams or Roberta Vinci.