Nacho Fernandez says Real Madrid's players are working on the basis Santiago Solari will remain in charge for the whole season after the interim head coach oversaw a 4-0 Copa del Rey win over Melilla in his first match at the helm.
The likes of Antonio Conte and Roberto Martinez have been linked with succeeding Lopetegui on a full-time basis, but Nacho insists he and his team-mates are only focused on the present.
After Madrid's comprehensive success against third-tier Melilla, Nacho told beIN SPORTS: "We will work as if he [Solari] is here for the full season. He is from here; he is experienced; he has won titles with Madrid.
"We, the players, don't have to make these decisions and we will see what happens but he's a great coach.
"The squad was with Lopetegui, but we didn't have any luck. Now we have a new coach, who is excited, and we will fight to the death for him, too."
Nacho acknowledged the days following Madrid's 5-1 loss to Barca had not been easy.
"It has been a difficult time after the Clasico, where he had a result which we hadn't expected," the Spain defender added.
"But this is football and, luckily, we had a game very soon after, which we wanted to win and above all score goals in. Obviously, it's painful to lose like the other day but thankfully there are more games to come."
Next up for Real Madrid is home match against Real Valladolid on Saturday.