As long-standing Welterweight champion Georges St-Pierre prepares to return to the Octagon after almost 19 months away, it becomes important to remember what got GSP to the lofty status he sits today. There has been much talk surrounding GSP's inability to finish opponents as of late, his tendency to fight very safe, and questions surrounding his severe knee injury. All valid questions to be sure, but the bottom line is GSP has been a dominant champion, and has finished off some of the best Welterweights to ever fight in the UFC. Let's take a look at the five most defining fights of his career: 

TKO victory over Matt Hughes at UFC 65:

The number one fight of GSP's career to date is a defining knockout of Matt Hughes in early 2007. GSP had previously lost to Hughes, the longtime division king, via armbar submission. St-Pierre has since stated he was scared of Hughes in that first bout, but in the second, he came out with dynamic striking and nailed Hughes with a brutal headkick. A few punches later, and GSP was the new 170 lb. king with a bright future ahead of him. 

TKO victory over Matt Serra at UFC 83:

Another defining victory, this time in his hometown of Montreal, came almost a year after GSP suffered only the second loss of his career in a stunning TKO to Serra. Since admitting that he had taken Serra too lightly, he came in visibly focused on avenging the defeat. Dominating Serra, he took the fight to the ground and unleashed a relentless series of knees to the body of Serra, earning the TKO.

Corner stoppage over BJ Penn at UFC 94:

BJ Penn, as mercurial as his career has been, is no doubt one of the most talented fighters to grace the Octagon. He attained championship status at both Lightweight and Welterweight, an unprecedented feat. However, his battle with GSP in Las Vegas was a bit one-sided, as St-Pierre battered the former champ until his corner threw in the towel after the fourth round. An excellent showing of just how far St-Pierre had progressed.

TKO loss to Matt Serra at UFC 69:

The only loss on this list is here because it was a wake-up call for St-Pierre. Serra was a historic underdog to GSP at UFC 69, yet he came out looking to have the best in the striking department over GSP. He nailed GSP with several crisp shots until he landed a brutal right, sending St-Pierre to the canvas. A few more punches later, and GSP's title was gone. Perhaps that was the best thing for St-Pierre, as he came back stronger and more motivated than ever, reeling off nine consecutive victories since while never being in any real danger. 

Unanimous decision win over Josh Koscheck at UFC 124:

This fight, which was the culmination of St-Pierre and Koscheck's stint as coaches on The Ultimate Fighter, had a ton of buildup and trash talk thanks to the polarizing antics of Koscheck. GSP chose to keep his mouth shut in preparation for the fight. Obviously he had the last laugh in the Octagon, peppering Kos with so many jabs that he broke the right orbital bone over Koscheck's eye. GSP shut the mouth that never seems to stop running and furthered his already impressive legacy.