ALLEN PARK, Mich. — There were ample reasons for fans to come out and see the start of joint practices between the Detroit Lions and New York Giants, which began on Tuesday at the Lions' team facility. The immediate assumption might be that watching two former No. 1 overall picks, the Giants' Eli Manning and the Lions' Matthew Stafford, might be a big reason.

And that would not be wrong, per se. Except that the showcase showdown on Tuesday came down to one pretty intriguing head-to-head battle: Lions cornerback Darius Slay vs. Giants receiver Odell Beckham Jr.

It was fair game to speculate how Beckham's speed and cutting ability might have been affected heading into this season by his season-ending ankle injury in 2017. Practice reports out of Giants camp have indicated that Beckham has looked excellent, and Tuesday's performance backed that up.

Don't take our word for it? Listen to what Slay, one of the more confident and talented cover men in the NFL, had to say about it.

"Oh no, he looked the same," Slay told us when we asked whether it looked like Beckham was less than a year removed from a shattered ankle.

Earlier, Slay said: "He looks like he's going [well]. He's catching the rock, running the rock. He's always been explosive. He's never going to lose that, except when he turns 50, I suppose.

"But he's always been explosive. Other than that, he's Odell. That's just it." 

The All-Pros have a history, having faced each other each of the past two seasons. Slay got the upper hand more often than not in those games, holding Beckham to 10 catches for 100 yards and a touchdown — well below his per-game average. On the other hand, Beckham appeared to get the edge on Tuesday, making some impressive catches ... and not just his patented warmup one-handers.

"I've been playing Odell going on three years, so it's nothing new," Slay said. "It's about coming out here and getting in some great work." 

After practice, Slay played down the idea that today's matchup, which saw him covering Beckham quite a bit head up, was somehow personal.

"Man, it's not really taking it personally," Slay said. "But I take it at a high level of competitiveness. It's not personal. ...

"I come out here to work, do my job, call it a day."

It was a nice surprise to be treated to this battle considering we weren't sure how much Beckham has been held back in some team work, per Giants beat writers, through the first few weeks of camp. There was even some doubt coming into the week just how much work Beckham might put in, especially after new Giants head coach Pat Shurmur held OBJ out of the preseason opener against the Cleveland Browns.

But on this day, he worked extensively through most of the individual and team periods and beat Slay on a sideline catch in seven-on-seven work, able to walk in for a would-be TD. Beckham did not speak with reporters following practice. He was seen headed to the weight room during player access.

Slay also downplayed the idea that he and OBJ matching up somehow were the biggest show on the field on this day.

"Shoot ... man, I don't know about that," he said. "I mean, everybody come out here to see everybody. It's the whole teams. It's the Detroit Lions and New York Giants."

That said, the biggest roars from the gallery came when Beckham was targeted by Giants quarterbacks, most often Manning, who had a very strong day throwing the football. (Also having a good day: Giants tight end Evan Engram, who is said to be having an excellent camp following a breakout rookie season.)

When Slay won reps vs. Beckham, the partisan Lions fans roared. But there were Giants fans there, too — or were they Beckham fans? Either way, they made their noise as well when the receiver seeking a record-breaking contract made superstar-caliber plays.

Even if Slay believes it was not about two players on two 90-man rosters, it's hard to deny that this was a high-level matchup, the likes of which we are not often treated to except for on regular-season or playoff gamedays.