The counting numbers don't necessarily jump out at you: 57 receptions, 965 yards, 10 touchdowns. That's a pretty good touchdown total for one player, but otherwise, the totals just look like a decent starting wide receiver.
What makes it impressive is that he did it in only 70 targets. That's a catch rate of over 81.4%, just shy of 13.8 yards per target, and a touchdown rate of about 14.3%. All three of those numbers are remarkably good.
The week 17 statistics haven't posted yet on the sites that I'm looking at. Through week 16, only 10 players in the league had a catch rate over 81.4% (minimum 29 receptions). Most of them are running backs taking a bunch of dump-offs, with Saints receiver Michael Thomas the only one averaging over 9 yards per reception. For comparison, Lockett averaged over 16.9 yards per reception.
Meanwhile, only one player in the league had a touchdown rate over 14.3%: Chargers wide receiver Mike Williams. Only one other player besides Lockett had a touchdown rate over 12%: Anthony Miller of the Bears. Both of those players had a catch rate under 64%.
But what's really outlandish is Lockett's 13.79 yards per target. To put that into perspective, no one else in the entire NFL with at least 35 receptions averaged over 11 yards per target. If you restrict to the 112 players with at least 35 receptions, the second highest in yards per target (Mike Evans of the Buccaneers at 10.91) was barely closer to Lockett's final 13.79 than he was to the league average among that group (8.02).
According to Pro Football Reference, there have only been nine seasons since 1992 where anyone had over 2 receptions per game and at least 12 yards per target. Before this year, Jordy Nelson's 2011 season of 13.16 yards per target held that record. Lockett just shattered that.
As Lockett did remarkably well in three of the four components that go into quarterback rating, I checked on interceptions, too. As the play by play didn't always specify the target, I had to watch highlights (lowlights?) to verify that none of Wilson's interceptions this season targeted Lockett. Thus, a little quick arithmetic reveals that Wilson had a perfect 158.3 quarterback rating when targeting Lockett.
The four components of quarterback rating are all capped artificially. Well, the interception rate cap isn't so artificial, as you can't have an interception rate below 0%. If we ignore the caps, Wilson would have had a quarterback rating of 175 (exactly) when targeting Lockett.
So I decided to ask, how many quarterbacks had an individual game this season in which, for just a single game, they managed to match the efficiency of Wilson to Lockett for this entire season?
If you look only at completion percentage by a starting quarterback, 17 quarterbacks had a game in which they completed over 81.4% of their passes. Most of them only had one. Roethlisberger and Manning had two, while Brees and Rivers had three.
To have 13.9 yards per attempt was much rarer. There were only 4 instances of that, out of 480 instances of a quarterback starting a game. No quarterback in the league averaged 13.9 yards per attempt over the course of two games in which he started, even if you get to cherry-pick the two games. Ryan Fitzpatrick (!) did come very close to that, though, and in multiple ways. (In addition to 14.9 yards per attempt in a game in which he started, he had 12.2 in another start and 12.9 in a game which he did not start, but did have 15 attempts.)
So let's see if we can find a single game where a quarterback was as efficient as the Wilson to Lockett connection was for the entire season. Using Pro Football Reference, I limited a search to games with 0 interceptions, at least 10 attempts, at least 60% completion percentage, and at least 10 yards per attempt. That produced only 7 quarterback single-game performances all season with an uncapped quarterback rating above 175. Russell Wilson was the only quarterback with more than one. So the Wilson to Lockett approach for the entire season was, more often than not, rated more highly than the highest rated starting quarterback in a given week.
Just for fun, I decided to pick out the highest rated performance by a quarterback that met those requirements each week. Again, this is using the quarterback rating formula with uncapped ratings. The results are:
Week 1: Ryan Fitzpatrick 21-28, 417 yards, 4 TD, 174.3 rating
Week 2: Patrick Mahomes 23-28, 326 yards, 6 TD, 190.5 rating
Week 3: Ryan Tannehill 17-23, 289 yards, 3 TD, 159.5 rating
Week 4: Mitchell Trubisky 19-26, 354 yards, 6 TD, 196.6 rating
Week 5: Drew Brees 26-29, 363 yards, 3 TD, 163.4 rating
Week 6: Matt Ryan 31-41, 355 yards, 3 TD, 125.6 rating
Week 7: Matthew Stafford 18-22, 217 yards, 2 TD, 141.7 rating
Week 8: Deshaun Watson 16-20, 239 yards, 5 TD, 201.9 rating
(honorable mention: Russell Wilson 14-17, 248 yards, 3 TD, 190.3 rating)
Week 9: Nick Mullens 16-22, 262 yards, 3 TD, 157.8 rating
Week 10: Ben Roethlisberger 22-25, 328 yards, 5 TD, 196.8 rating
Week 11: Eli Manning 17-18, 231 yards, 2 TD, 171.3 rating
Week 12: Marcus Mariota 22-23, 303 yards, 2 TD, 165.7 rating
Week 13: Russell Wilson 11-17, 185 yards, 4 TD, 179.8 rating
Week 14: Ryan Tannehill 14-19, 265 yards, 3 TD, 174.2 rating
Week 15: Deshaun Watson 22-28, 294 yards, 2 TD, 135.1 rating
Week 16: Kirk Cousins 21-28, 253 yards, 3 TD, 137.9 rating
So let's make a composite quarterback by picking the best rating from each week. That totals 316-397 for 4681 yards, 56 touchdowns, and 0 interceptions. Obviously, that would be by far the greatest quarterback season in NFL history. Of course you can produce ridiculously great stats by cherry-picking whose numbers you'll pick after each game.
And it also produces a rating of 164.6. Which is less than the 175 that Wilson to Lockett got for the entire season. Wilson throwing to Lockett was more efficient for the entire season than if we picked the best quarterback each week, and chose independently for each week. Lockett's season was that ridiculous.