She should have been walking down the aisle last weekend, but instead she was racing down the streets.  Tennis ace Caroline Wozniacki has been a model of strength in the face of heartbreak in recent months, culminating in her turn in the New York City Marathon on the same weekend she originally planned her wedding for. Fining her feet among 50,881 runners, the Danish beauty's marathon debut raised a phenomenal $81,000 for her Team For Kids charity. The 24-year-old crossed the line after three hours, 26 minutes, 33 seconds, to a warm embrace from waiting friend Serena Williams. The pals spent the night before the race at an ice hockey game. All smiles: Wozniacki's good friend Serena Williams was on hand for race prep the night before Wozniacki, who is currently rated as the World No. 8, said of the race: “I never tried anything this hard.” “This is the toughest physical challenge ever. You have to keep going, keep going. I just kept grinding out there.” It's another coup for Caroline, who appears to have flourished since her shock split from Irish golf champ Rory McIlroy. The way they were: Caroline with former fiancé Rory McIlroy  The couple went their separate ways in May when Rory called off their engagement the week after invitations to their wedding had been issued to friends and family. At the time, Rory said: "The problem is all mine".