Sergio Ramos, Lucas Vazquez and Vinicius Junior scored the goals in the first leg at the Bernabeu, and the European champions will be looking to finish the job when they travel to Leganes on Wednesday night.
Leganes might have knocked Madrid out of last season's Copa del Rey with a 2-1 win at the Bernabeu, but the team from the outskirts of the Spanish capital suffered a 3-0 loss at Los Blancos in the first leg of their last-16 clash last week.
Mauricio Pellegrino's side actually played well for long spells of the first leg, but Madrid were decisive in the final third of the field as they took a huge step towards advancing to the quarter-finals of the competition.
Copa del Rey semi-finalists last season, Leganes have finished 17th in La Liga in each of the last two campaigns. Los Pepineros currently occupy 13th in Spain's top flight this term, however, and will enter this particular match off the back of a 1-0 win over Huesca in the league on Saturday.
The Copa del Rey is not high on Leganes' list of priorities this season as their sole focus will be on securing another campaign of La Liga football. They famously knocked Madrid out of the Copa del Rey last term, but it is going to take some effort to overcome their capital rivals on this occasion.
Leganes have only lost seven of their 19 La Liga matches this term though, which is just one more than Madrid. They have also conceded just 21 times in Spain's top flight this season, which is fewer than their opponents in this match and shows their improvement under Pellegrino during the 2018-19 campaign.
Leganes will want to give a positive account of themselves in this match, but there is no question that the players will have more than one eye on the trip to Barcelona in La Liga this weekend.
Recent form: WDLDWL
Recent form (all competitions): DDDLLW
Madrid returned to winning ways in La Liga at the weekend, with Dani Ceballos scoring late in a 2-1 success at Real Betis. It was a much-needed victory for the capital giants, but Santiago Solari's side are still 10 points off leaders Barcelona in Spain's top flight.
Los Blancos have booked their spot in the last-16 stage of the Champions League, but it is difficult to imagine the capital giants landing a fourth straight European title when considering the form they have shown this season.
As a result, there is huge pressure on Madrid in the Copa del Rey this season. They have not actually won the competition since 2014 though, and as mentioned above, were dumped out of the competition by Leganes in the quarter-finals last season.
Head coach Solari will certainly make changes for this match ahead of Saturday's huge home game against Sevilla. Madrid have a pretty extensive injury list at the moment, however, and that could cost them dearly as they look to continue competing on three fronts in the second half of the campaign.
It was always going to be difficult to cope without Cristiano Ronaldo's goals, but Gareth Bale has been unable to step up to the extent that many believed he would. The Welshman only has four La Liga strikes this season and is currently on the sidelines with a calf problem.
It has been a turbulent campaign for Madrid, who sacked Julen Lopetegui following a poor start to the campaign. They are all but out of the title race due to Barcelona's current form, but the Copa del Rey does provide a genuine chance to land some domestic silverware, which has been hard for the club to find in recent years.
This match could almost be seen as a free hit for Madrid due to their strong lead, but a couple of early goals for Leganes on the night could make it a difficult evening for what will be an experimental XI.
Recent form: DWLWWW
Recent form (all competitions): WWDLWW
Levante boss Pellegrino will make changes from the team that started against Huesca at the weekend and there should be a recall for on-loan Middlesbrough attacker Martin Braithwaite, who impressed in the first leg.
As for Madrid, head coach Solari has a whole host of injury concerns.
Isco could feature in a false nine position for the visitors, with Vinicius and Lucas also making the XI.
Leganes possible starting lineup:
Cuellar; Juanfran, Bustinza, Siovas, Tarin, Silva; El Zhar, Perez, Garcia, Merino; Braithwaite
Real Madrid possible starting lineup:
Navas; Odriozola, Ramos, Nacho, Reguilon; Ceballos, Casemiro, Valverde; Vinicius, Isco, Vazquez
Head To Head
As mentioned, Leganes beat Madrid in the quarter-finals of last season's Copa del Rey, with a 2-1 victory at the Bernabeu in the second leg seeing them progress on away goals.
Los Blancos recorded a 4-1 victory when the pair met at the Bernabeu in La Liga earlier this season, however, and have won seven of their eight meetings in all competitions, including the first leg last week.
We say: Leganes 1-2 Real Madrid
Both managers will make changes from their respective league matches at the weekend, but we still expect Madrid to triumph. A 2-1 success on the night would see the European champions progress 5-1 on aggregate.