Silva would defend his title for the eighth time that night, behind an iconic front head kick on Vitor Belfort. UFC president Dana White has credited that kick, and a contentious rivalry with Chael Sonnen, for turning Silva into a legitimate pay-per-view draw.
Johnson was a 24-year-old bantamweight at the time. It remains the only event he and Silva both competed on. They did cross paths that night, but it was very brief.
"He was in a different workout room and I wanted to go in and meet him," Johnson said. "I don't speak Portuguese, though. I basically walked right in and said, 'Hey! Big fan!'
"He looked up and said, 'What's up, buddy!?' And then they kicked me out. That was it."
This weekend, Johnson (25-2-1) will attempt to tie Silva's all-time record of 10 consecutive UFC title defenses, which has long been considered one of the greatest feats in this sport's history.
Consecutive title defenses by each current UFC champion
Standing in Johnson's way of tying the record is unheralded Brazilian contender Wilson Reis (22-6), who fights out of Alliance MMA in San Diego. The fight headlines UFC Fight Night on Saturday, inside Sprint Center in Kansas City.
Ever since that chance encounter at UFC 126 all those years ago, Johnson has been establishing his own legacy -- but also chasing Silva's in a way. His ultimate goal is to be considered the greatest fighter of all time, and Silva is the one he'd need to take that from.
In terms of skill set, a case could be made that Johnson has already proven himself the most complete talent of all time. But history likes to rely on records and numbers to decide such things. So, for Johnson, the important number has been Silva's 10 title defenses.
"We've never chased Anderson specifically," said Matt Hume, Johnson's longtime head coach. "We were chasing making DJ the best fighter of all time.
"To say he's the best pound-for-pound fighter on Earth is a fact at this point. To say he's the greatest of all time is within reach. Tying the record on Saturday puts us right there, breaking it will put us over the top."
As has long been the case with Johnson, 30, it's amazing to consider him entering the conversation of "greatest fighter of all time" on Saturday, and yet still being overlooked.
Whereas Silva had his Belfort knockout and Sonnen rivalry, Johnson is still waiting for that "moment" that turns him into a mainstream star. Perhaps it will literally take breaking Silva's record, which could then lead to super fights, bigger paydays and mainstream exposure.
Johnson has made it clear he would only consider a move up in weight for a significant pay hike. If the UFC never meets that demand, his long-term plan is at flyweight.
"Legitimately, within his weight class, he can prove he's the greatest ever," Hume said. "But that doesn't mean we won't pursue other challenges in other weight classes when the time is right."
In terms of the event and spectacle, that's up to the promoter. In the respect of a fighter dominating competition in a manner that leaves no doubt, Silva and Johnson stand alone at the top.
While it's become easy to predict the results of Johnson's fights -- he hasn't lost in nearly six years -- predicting his eventual place in history is more difficult.
Whether it's due to his size, fighting style, disinterest in trash talk or lack of UFC promotion, Johnson's dominance at flyweight has not captured the attention Silva's did at middleweight. In some ways, maybe that's helped him from a competitive standpoint. At the end of Silva's title run, he looked, at times, exhausted from holding the belt so long. Johnson looks like he could keep this up for another 10 fights.
And if he does, will he be remembered as the greatest ever? Or does Silva have an insurmountable lead in that regard, because he came first and because there were more eyeballs on his run?
"I don't know," Johnson admitted. "But history is always changing. I hope people can remember me as the greatest. Who knows?"