Madrid and Barcelona are the only teams with a perfect start after three matches, earning healthy gaps to other potential title contenders.
Brazilian legend Ronaldo paid around 30 million euros ($35 million), according to Spanish media reports.
Their strong showings came after Luis Enrique left both players, along with Atletico's Jorge 'Koke' Resurreccion, out of his squad for upcoming matches against England and Croatia.
The thrashing lifted Barcelona above Real Madrid at the top of the La Liga standings on goal difference after three games.
At 1-1 in the 48th minute and with Leganes holding its own, Karim Benzema skillfully headed in an out-swerving cross from Marco Asensio despite tussling with defender Jonathan Silva.
The defeat would have been worse if not for the video assistant referee waiving off a third goal that was initially awarded on the pitch.
This year the Premier League's transfer window shut before the English top flight season got underway and Lopetegui said he would be in favour of a similar setup in Spain.
Gareth Bale and Karim Benzema are keeping Real Madrid's attack alive in the absence of Cristiano Ronaldo.
Barcelona were second best for large parts of their visit to the Jose Zorilla, however a second half strike from Ousmane Dembele ultimately proved the difference.
The Spanish football league has signed a 15-year partnership with Relevent Sports that will, in theory, see a regular season game played in the US among other partnerships.
The Spanish Footballers Union said it was holding a meeting on Wednesday to discuss the issue and added to the criticism which it made at the time of the announcement.
Valencia's Rodrigo struck a fine second-half volley to earn a 1-1 draw at home to Atletico Madrid in an end-to-end clash as both sides got their Liga campaigns underway
Gareth Bale scored in Madrid's Spanish league opener and set up the other goal in a 2-0 win over Getafe in Sunday's Madrid derby.
Lionel Messi cleverly sent his free kick underneath Alaves' wall to open the scoring in the 64th minute of Barcelona's 3-0 win at Camp Nou Stadium on Saturday.
Rela Madrid will begin la Liga without Cristiano Ronaldo. Last season Real had finished 17 points behind champions Barcelona and below Atletico Madrid.
After Cristiano Ronaldo and Zinedine Zidane exits, Real Madrid get their first test against crosstown rival Atletico Madrid in the UEFA Super Cup.
A statement from La Liga said all 380 league matches for the new season, which begins on Friday, would be available to viewers in India, Afghanistan, Bangladesh, Bhutan, Nepal, Maldives, Sri Lanka and Pakistan.
Atletico Madrid managed to tie down their most coveted players during the transfer window and are ready to launch another title challenge.
La Liga season begins on Friday without one of its most emblematic players, Cristiano Ronaldo, and with video technology (VAR) being introduced for the first time in Spain’s top flight.
Ousmane Dembele rifled home a long-range strike on Sunday to help Barcelona to a 2-1 win over Sevilla in Tangier and their first piece of silverware for the season.
Gerard Pique welcomed the prospect of fewer games -- although he conceded that playing the game in Tangier, Morocco, was not ideal.
Lionel Messi, who has earlier led Barcelona in Iniesta's absence will officially hold the mantle after the midfielder moved to Japan to play for Vissel Kobe.
El Mundo reports the Portuguese player Cristiano Ronaldo had paid two million extra last year for his image rights sold in 2014.
Former Arsenal midfielder Santi Cazorla returns to Villarreal after a series of injuries that kept him out of the football field for several months.
La Liga runners-up Atletico Madrid announced on Thursday they have signed Croatia striker Nikola Kalinic from AC Milan for an undisclosed fee