He was passing through on his way to the kitchen to get some food, upset with himself after being declared academically ineligible for the second time of his brief college career, when his eyes locked onto the image staring back.
"My mother was at work; nobody was home," Cruz said Saturday on a quiet walk to the exit of MetLife Stadium. "I was just looking in that mirror, wondering what I was going to do with myself. Was this going to be my life? Was I going to accept this? I was a failure.
"That was my turning point."
How's that man in the mirror looking right about now?
"This is just surreal to me," said Cruz, who is seeing his first significant action this season after proving himself as an undrafted rookie last year.
Forget about the records, though. With 164 yards on three catches, Cruz's big touchdown with 2:27 left in the second quarter shifted the momentum on Saturday entirely -- sparking his team to a 10-7 halftime lead after the Jets had previously controlled the game.
It was the type of moment that will need to be replicated in some fashion next week against the Dallas Cowboys -- with the NFC East title on the line -- if the Giants are going to surge into the playoffs. Quarterback Eli Manning needs this type of help, as evidenced early in Saturday's game, when too many of his passes were dropped.
"We obviously had some issues with our receiving corps, and I thought he was the one guy that could give us that kind of play -- and he certainly did," Giants coach Tom Coughlin said. After the game, Jets coach Rex Ryan called Cruz's touchdown "demoralizing," while dubbing Cruz, who first broke out with a three-touchdown game against the Jets in the 2010 preseason, a "Jet killer." But lately, Cruz's success has extended beyond this rivalry.
Four times in the last six games, he's eclipsed 100 yards.
"I don't even know how to put this into words," Cruz said. "To be first in single-season receiving yards? It's just amazing."
Mild-mannered and now level-headed, Cruz knows he doesn't much have time to reflect on his past, particularly at such an important juncture in the season. But when he considered the magnitude of the moment, there might be no better motivation than the memory of his past.
Cruz grew up a Cowboys fan in Paterson, N.J., turned on to Dallas by his father without having much say in the matter. So the fact that he'll follow up his record-setting performance not far from his hometown in a big game against his childhood team is only adding to this dream.
"After that day I looked at myself in the mirror, I had a 3.8 GPA, I got back into school, I picked a major," Cruz said. "I was good to go."
His is an inspiring story, one that proves even a change of attitude later in life can yield positive results. Cruz recalled a time in his late teens when he was unmotivated academically. He planned to play college football at the University of Massachusetts -- but his failure to qualify led to a detour to Bridgton Academy, a postgraduate school in Maine. Once finally accepted into Massachusetts, he again struggled with classes, this time nearly ending his football career before it began.
That's when Cruz, finally realizing the impact his decisions were having on his life, experienced the moment that would change it all. A moment, in retrospect, that Giants fans everywhere can certainly appreciate.
On the occasions when Cruz returns to Paterson to visit his mother these days, he doesn't always notice the mirror that still hangs from a wall in the living room. Sometimes, though, when he catches his reflection at just the right time, it triggers a memory of a period in his life when he couldn't stand the person staring back.
"Every once in a while, I look at that mirror and still get goose bumps," Cruz said.
You can bet his next trip home will prove to be one of those days.