October 11, 2020 | 8:13pm | Updated October 11, 2020 | 8:14pm

Birds fly. Fish swim.

The sun rises in the East and sets in the West.

There are irrefutable truths. Here is another: The Giants lose.

Every day, in every way. This time, the script was flipped in that the Giants took a 17-3 lead Sunday and you had to wonder: Are the Cowboys this bad?

Answer: No, but the Giants are.

An avalanche of mistakes, missed opportunities and two touchdowns taken off the board kept the Giants winless in head coach Joe Judge’s first season. They were overtaken and beaten 37-34 at AT&T Stadium on Greg Zuerlein’s 34-yard field goal as time expired. The Giants lost a game and the Cowboys lost Dak Prescott, their outstanding quarterback, to a gruesome right ankle injury — diagnosed as a compound fracture — midway through the third quarter.

Tied at 34, the Giants had a chance to finish the deal, getting the ball with 1:50 left, but Daniel Jones was pressured on every pass and they had to punt the ball away. The Cowboys had 52 seconds to work with and, on cue, the Giants defense caved in.

Prescott’s replacement, Andy Dalton, took the Cowboys 72 yards in only four plays, getting a brilliant sideline catch by Michael Gallup for 19 yards and then the dagger: A 38-yard lob to Gallup over cornerback Ryan Lewis with three seconds remaining to set up the game-winning kick.

The Giants had so many chances to win the game. They had two touchdowns taken off the board by their own mistakes. They showed moxie and yet they had nothing to show for it.

The Giants are 0-5 for the first time since 2017 and this loss was a first in that it came in the NFC East, where no team is out of it until it is out of it. The bottom-feeding Giants, though, are not in anything other than a heap of trouble.

The Cowboys (2-3) are now alone in first place in the come-one-come-all NFC East. They sit atop the NFL’s worst division, ahead of the Eagles (1-3-1), Washington (1-4) and the winless Giants. The Giants and Washington square off in Week 6 at MetLife Stadium in a battle for last place.

The Giants fell to the Cowboys today in heartbreaking fashion.
The Giants fell to the Cowboys today in heartbreaking fashion.Getty Images

Trailing 31-23 after Prescott went down and Ezekiel Elliott scored on an 11-yard run with 5:03 left in the third quarter, the Giants did not fold. They came up short on a promising drive and settled for Graham Gano’s fourth field goal to pull within 31-26. On the next play, Dalton fumbled the snap and Blake Martinez recovered on the Dallas 17. The Giants cashed in on Devonta Freeman’s 5-yard TD run. On the two-point conversion, left tackle Andrew Thomas reported as eligible and was wide open in the end zone to collect Jones’ floater to put the Giants up 34-31 with 8:46 remaining.

A face-mask penalty on Markus Golden jump-started a Cowboys drive that ended with Greg Zuerlein’s 40-yard field goal to tie the game at 34 with 1:56 to go.

There was an inkling this might be different. The Giants got Evan Engram’s first NFL rushing touchdown, an interception return by linebacker Kyler Fackrell and a 55-yard field goal by Gano to take a 17-3 lead early in the second quarter, already surpassing their season average of 11.8 points a game.

By halftime, the Giants were down 24-20 because of a series of blunders great and small. Yet another Jones fumble — this one triggered when DeMarcus Lawrence obliterated rookie left tackle Thomas — turned into a disaster when Anthony Brook returned the turnover 29 yards for a touchdown. The Giants used trickery and should have had a 24-17 lead on a fake punt that worked to perfection, but an illegal shift penalty on Cam Fleming caused by just a split-second early call for the ball by punter Riley Dixon took the points off the board. The Cowboys then closed out the half by befuddling the Giants with a gimmick play that resulted in Prescott hauling in his first career touchdown catch, an 11-yard scoring play on a pass from receiver Cedrick Wilson just 16 seconds before halftime.

The Giants did not own a lead since the closing seconds of the first half. They were down 3-0 but were not behind for long. The Cowboys diagnosed an end-around to Engram, but Engram used his agility to motor past defensive lineman Everson Griffen for a 3-yard touchdown run.

Yes, a touchdown.

The Giants came into the game with zero touchdowns in their previous 21 offensive possessions and, for the first time since 1998, went back-to-back games without scoring a touchdown.

About a minute later, the Giants had their second touchdown, a veritable scoring spree for a team that through four games was last in the NFL in points and yards.

These points came via their defense. Prescott threw too high for Elliott, the ball deflecting off Elliott’s hand and into the grasp of Fackrell for an interception. Fackrell motored up the right sideline and dove into the end zone to complete a 46-yard touchdown return. The Giants had two touchdowns in 65 seconds.

In the end, the Giants had nothing but another loss.