Murray, 27, needed five match points before he secured victory and will next look to clinch a double over Nadal in the Abu Dhabi exhibition tournament having defeated the Spanish great in the final in 2009.
“Lopez had break points and I had a lot of match points so I’m happy just to get through,” said Murray.
In Thursday’s late match, Australian Open champion Stan Wawrinka eased past Spain’s Nicolas Almagro 6-3, 6-2.
Wawrinka will next face world number one Novak Djokovic in Friday’s semi-finals. -AFP