Taken No. 7 overall by the Los Angeles Chargers, Williams was an after-through at best while hearing whispers of "bust" after recording only 11 catches for 95 yards in 10 games in a forgettable rookie season.
Williams also did not find the end zone in his first year, something he has rectified this season by scoring 10 times on just 34 receptions through 14 games.
However, Williams saved his coming-out party for Los Angeles' biggest game of the year, hauling in a pair of touchdown passes and scoring on a 19-yard touchdown run as the Chargers pulled off a dramatic 29-28 win over the Kansas City Chiefs on Thursday night.
"He stepped up big," said Los Angeles coach Anthony Lynn. "Mike has been playing well all year. We only have one football. You can't get the ball to everyone like we would like all the time, but Mike has been playing well all season. He just stepped up and made the plays that we know he can make."
Did he ever. Los Angeles lost No. 1 wide receiver Keenan Allen to a hip injury in the second quarter Thursday night, but Williams filled the void with a season-high seven reception. And he was at his best with the game on the line.
Williams hauled in a tying 1-yard touchdown pass from quarterback Philip Rivers with 4 seconds to play and then was wide open for the winning 2-point conversion as Los Angeles eschewed a chance at an extra point and gambled for the victory.
"There's never been any doubt in this locker room about Mike, but I think that the whole world knows now why he was picked No. 7," Rivers said. "He's got (10) touchdowns and he pretty much, in his own way, (even though) all the receivers contributed, took over the football game. I mean, he scored on a reverse, he caught the other two touchdowns, he caught the two-point conversion, he caught big third down conversions (and) he was (gaining yards off) run after catch.
"(We) hadn't seen him do as much of that because he hadn't been in those situations. ... Mike Williams (was) on fire."
Williams flashed his big-play ability during his senior year at Clemson. He had 98 receptions for 1,361 yards and 11 touchdowns -- one more score than his previous three seasons combined.
The 6-foot-4, 220-pound Williams started his huge night against the Chiefs with a 3-yard scoring pass in the second quarter to cut the deficit to 14-7. He then took a handoff on a reverse and burst up the middle for a 19-yard score, setting up his late-game heroics.
"It's just being a big, physical receiver," Williams said. "That's the main thing, just being a big physical receiver. Those are the plays I used to make in college. Those are the plays I'm used to making. Just go make a play."
It marked the first career rushing touchdown for Williams, who became the third receiver in franchise history to notch a receiving and rushing touchdown in the same game.
"I can't say enough about him," Chargers tight end Antonio Gates said. "He's thrived. Obviously, he's still got some things that he can still grow at, but to watch him go out and perform like that on the big stage tonight (was impressive). Obviously, Keenan went down, and he was able to step in huge. It says a lot about our team.
"More so than anything, just the depth of our team and when guys' numbers are called, (they're) willing to step in and be able to make the plays we need to win. He did (an) unbelievable job to help us win this game."