Dallas Cowboys coach Jason Garrett said it best.It’s “nut-cutting” time for his team.His words. Not mine.Garrett was talking about the circumstances on the final drive in Sunday’s 24-21 victory against the New York Giants.But he was also talking about the rest of the season.The Cowboys (6-5) are tied atop the NFC East with the Philadelphia Eagles with five games left.They can build on Sunday’s victory against the Giants with a win Thanksgiving Day against the Oakland Raiders.Or they can fall back into the win-one, lose-one mode of the past decade and chance missing the playoffs for the fourth consecutive season.How the season turns out remains to be seen as the Cowboys remain challenged defensively because of injuries and personnel decisions.But one thing is clear after Sunday’s victory against the Giants: if they fall back, it won’t be from a lack of leadership.Quarterback Tony Romo’s play, guidance and calm demeanor on that final drive in New York was the epitome of leadership.Certainly, the Cowboys’ lack of playoff success since Romo took over has been well-chronicled as have their failures in important December and January games.Those results are bigger than Romo simply not being able to get it done when it matters most. His team-record 19 come-from-behind wins in the fourth quarter and overtime speak to that as does his fourth-quarter quarterback rating, the highest in NFL history.Romo won’t get his full due until he wins something significant in the playoffs, but the notion that his lack of leadership is reason for the Cowboys’ struggles is madness.What you saw Sunday was Romo displaying courage and leadership at a time when everyone believed he and the Cowboys were set for failure.Gone was a 21-6 lead. The Cowboys were looking like the Keystone Cops, from linebacker Bruce Carter and safety Jeff Heath’s brain lapse that gave the Giants an easy touchdown to the crazy, reckless fumble by Dez Bryant.It was cold. It was windy. The Giants had just tied the game with a touchdown and two-point conversion, and the crowd was whipped into a frenzy.Bryant said Romo walked into the Cowboys huddle and said, “We’re about to win and go home.”Fourteen plays, including three third-down conversions later, Dan Bailey kicked a 35-yard field goal as time expired, and the Cowboys went home with the win.“A lot is said about him [negatively],” tight end Jason Witten said. “But a lot of times it goes unnoticed how really special he is in those settings — the poise, the ability to find guys and take charge of the drill. He has done it time and time again. I thought he did a spectacular job on that last one. That’s what you want. You want your quarterback to take charge in those situations. He does as good a job as anybody in the NFL.”Actually, Romo’s leadership was on display well before the final drive. It was there on the sideline in calming Bryant down after his crazy fumble two series earlier that turned a second-and-10 into third-and-30.“Tony is a great leader. He’s one of the most humble guys I’ve ever met in my life,” Bryant said. “... When you’ve got a guy like that, all you want to do is play for him.”The Cowboys have several leaders in the locker room. You can count Witten, defensive end DeMarcus Ware, defensive tackle Jason Hatcher and linebacker Sean Lee as bonafide leaders on this team.But don’t leave out rising star Orlando Scandrick, who might have had the best single defensive performance of the season by the Cowboys in shutting down Giants’ game-breaking receiver Victor Cruz.Cruz finished with two catches for 27 yards in the game. One catch came against Scandrick.The one he did catch — a 5-yarder in the first quarter — turned into a 50-yard fumble return for a Cowboys touchdown because Scandrick ripped the ball out into the arms of safety Jeff Heath.While Romo is the picture of calm, Scandrick is an example of the fire burning inside the team that few people think it has.But it’s there. It’s there with him, Bryant, Lee and even Garrett.There is no bigger competitor on the Cowboys than Garrett. You don’t play 13 years in the NFL, even as a backup quarterback, if you don’t like competition.The win against the Giants was an example that Garrett’s messages of being your best in the moment and moving on from bad plays and bad games are resonating with his players.But it’s the fire that he has displayed on the practice field and in meeting rooms that made the biggest difference, including the move to get back in on the play-calling with a direct line to Romo on the headset.Garrett knew what was at stake in what was easily the biggest win of his career. How big?Asked afterward to compare the feeling Sunday to the euphoria of the 33-20 victory over the Giants on Nov. 14, 2010, Garrett was stumped.It was his first win as head coach after replacing Wade Phillips six days earlier.“That was big, too,” Garrett said after being reminded of the occasion.The Cowboys have set themselves up for bigger victories down the road.