1.UFC 158 is the first event in UFC history where the top three bouts on the card feature a fighter coming off a win vs. one coming off a loss.
2.St. Pierre has the chance to tie Matt Hughes' record for the most wins in UFC history at 18. He could also pass Hughes' record for most total title defenses in UFC welterweight history with eight
3.Diaz is the sixth fighter in UFC history to fight for an undisputed title after a loss, joining Randy Couture, Andrei Arlovski, Dan Henderson, B.J. Penn and Frankie Edgar.
4.Marquardt fights in the UFC for the first time since being cut in June 2011.
5.Johny Hendricks can tie Thiago Alves for third most UFC wins among active welterweights at 10.
6.Mike Ricci and Colin Fletcher, who face each other on the main card, both lost in the finals on their respective season of The Ultimate Fighter (TUF) reality show.
7.If St. Pierre fights to a decision, he will be just 39-seconds behind B.J. Penn for the most total fight time in UFC history.
8.All five of Diaz's UFC defeats are by decision.
9.Six fights on the card will feature a fighter coming off a win against a fighter coming off a loss.
10.George Roop will make his UFC Bantamweight debut on the card; marking the third different weight class he has competed in under the Zuffa banner (lightweight, Featherweight, bantamweight).
11.Ricci has fought eight of his 10 professional bouts in his home province of Quebec. He is 7-1 in those fights.
12.St. Pierre holds the current UFC record for most consecutive minutes of fighting without a finish while still earning a victory at 125.
13.Diaz can become the first man in the modern UFC history to hold the Strikeforce and UFC championship belts.
14.After putting together a six-fight UFC win-streak, Rick Story is 1-3 in his past four bouts.
15.According to the official UFC rankings, UFC 158 features five of the top seven ranked welterweights in the world.
16.Jordan Mein has finished his opponent in 21 of his 26 victories, 14 by (technical) knockout and seven by submission.
17.Diaz will become just the sixth man in modern UFC history to compete for the UFC and Strikeforce titles at some point in his career (Renato Sobral, Dan Henderson, Mauricio Rua, Jake Shields, Nate Marquardt).
18.Six of the 12 bouts on the card are welterweight contests.
19.Patrick Cote will attempt to string together back-to-back victories in the UFC for the first time since 2007 -- a span over 5.5 years.
20.Hendricks has won three fights in a row against top-10 opponents.
21.According to Fight Nomics, Marquardt and Ellenberger have 16 UFC knockdowns between them, the most of any pairing on the card.
22.St. Pierre is second to Anderson Silva for longest active win streak in the UFC at 10.
23.After fighting his first 26 professional bouts as a light heavyweight and middleweight, Patrick Cote will make his welterweight debut at UFC 158.
24.UFC 158 will mark St. Pierre's fourth consecutive bout in Canada.
25.Marquardt's last four losses have come by decision. Eight of 11 losses in the career of "The Great" are by way of decision.
26.St. Pierre is the longest tenured active welterweight on the UFC roster at nine years, one month and 16 days.
27.Hendricks has won "Knockout of the Night" in three of his past five UFC bouts.
28.Darren Elkins is undefeated (4-0) in the UFC featherweight division and 5-1 overall under the UFC banner.
29.In the 11 events the UFC has held in Canada, Canadian fighters are at 33-32 when facing opponents from other countries. There are seven Canada vs. the world bouts on the card.
30.According to Fight Metric, St. Pierre tops the UFC in takedowns landed (75), takedowns accuracy (78.1 percent) and total strikes landed (2,188).