After a dominant display in her semi-final triumph over Simona Halep, Pennetta proved her class again to deny Vinci, who caused one of the biggest shocks in recent memory by knocking out world number one Serena Williams in the last four.
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The 26th seed looked the sharper of the two Italians in the early exchanges, and she made a breakthrough in an extraordinary game as Vinci finally lost her serve after saving six break points.
Vinci showed the resilience which carried her through to the final as an unseeded outsider, and a couple of stunning strokes helped her to break back.
A tie-break was needed to split the two players in the opener, and it was Vinci who paid for errors at a crucial stage as Pennetta took charge.
Pennetta held her nerve with the lead in the tie-break, and in front of a crowd which included Italian Prime Minister Matteo Renzi, the 33-year-old secured a vital advantage by taking the first set.
Vinci struggled to produce a response to the setback as the excellent shots from the baseline which were key to the win over Williams evaded her.
Pennetta was in no mood to let her rival off the hook, and she capitalised on errors from Vinci to race into a 4-0 lead as her brilliant backhand started to deliver winners on a regular basis.
As dark clouds threatened to halt Pennetta's charge, Vinci proved that there was still fight left in her as she hit back to secure a break of her own with a morale-boosting winner.
Despite the New York crowd beginning to side with Vinci as they hoped for a deciding set, Pennetta remained composed to hold off a resurgent Vinci.
A memorable tournament was completed in impressive fashion as Pennetta broke to love before embracing Vinci at the net as she celebrated the biggest result of her long career.