Ramos put a free header over the bar from a free-kick while Esteban Granero just failed to connect with a neat pull-back from Kakabut Lyon held on for the win and a slender advantage.
Wayne Rooney, surprisingly left out of the United starting line up, also hooked a chance over, but at the other end fellow substitute Kaka rattled the home woodwork.
Former World Footballer of the Year Kaka came closest to breaking the deadlock for the visitors, but saw his second-half free-kick brilliantly saved by home goalkeeper Juan Pablo Colinas.
But, despite his inconsistent form and a season disrupted by tendinitis in his knee, Kaka wants to experience the high of being named the world's best player again.