Chosen
Chosen had a good run during the group stages, losing only to the group winner by 1 map and giving away a win to team fix on their home map dm2!? Their lineup is made up of 5-6 active players all of who we will probably see in action during the quarterfinal game.

O Clan
O Clan, one of the two active american teams playing in the EQL, their biggest issue is for sure their ping, even now with antilag on near but all servers, it still makes quite the difference. However most of their players have played many seasons in europe and are used to the high ping. Also they do have marvel, who if active can be a great asset to any team.

Conclusion
I can't see how Chosen could lose this, I don't expect O Clan to do well on the kenya maps and with Chosen's good form, it looks like near impossible for O Clan to take this. I could see them taking E1M2, while the "not-so-ping-dependant" DM2 is by far Chosen's best, so I don't expect them giving Chosen much trouble.

Expected lineups
Chosen: Fl4m3r, Hooraytio, Pyta, Rkd, Kalma/ junkass
O Clan: doum, karnage, marvel, vegeta

Previous encounter
2-0 (cmt4: 274-45, dm3: 243-88)

Expected outcome
Chosen, 3-1