Complex sentence: The actual pay-per-view opened with the first semifinal match of the WWE World Heavyweight Championship tournament, in which Roman Reigns faced United States Champion Alberto Del Rio (with Zeb Colter).
Split into simpler sentences: The actual pay-per-view opened with the semifinals in the tournament for the WWE World Heavyweight Championship. In the first semifinal match, Roman Reigns faced United States Champion Alberto Del Rio (with Zeb Colter).