The final three houseguests of Big Brother 15 participated in part 1 of the final Head of Household competition on the live feeds Thursday night.

Houseguests: Andy Herren, GinaMarie Zimmerman and Spencer Clawson

After evicting McCrae Olson on Thursday night's live eviction, Andy, GinaMarie and Spencer celebrated outlasting their former housemates. However, there is still one more eviction left until the final 2, so the alliance that has stuck together for so long will have to turn on each other.

Andy, GinaMarie and Spencer competed in part one of three of the final Head of Household competition. The competition involved the houseguests roller-skating on a rink while holding onto a bar above them. Whichever houseguest held on the longest would win part 1.

Spencer had difficulty from the start, choosing to use a walking method with his skates instead of gliding like Andy and GinaMarie. He soon lost control and slipped, eliminating him from the competition. The rink was then covered in foam and made slippery, which made things more difficult for Andy and GinaMarie.

Both remaining houseguests began careening out of control but Andy fell first. This meant that GinaMarie had won round 1 of the HOH competition. She automatically advances to part 3, which will be held on finale night. Andy and Spencer will compete in part 2 this weekend to determine who will face GinaMarie in part 3.

After the competition, GinaMarie made separate deals with both Andy and Spencer to take each other to the final 2 if one of them won HOH. Andy and Spencer had also made a final 2 deal earlier in the season. This means that one of the remaining houseguests will be disappointed when their presumed ally votes them out in the finale.

Big Brother 15 will air its next episode on Sunday at 8 p.m. on CBS, featuring the highlights from part 1 of the HOH competition and a look back at the season.

Watch GinaMarie's victory in the competition here:

Tags: Big Brother 15 Spoilers