Both teams started the game trying to pressure the ball and dominate possession on Saturday night, reports Efe news.
Although the hosts were the first to take the offensive initiative and won an early corner kick, Leganes managed to open the scoring just 10 minutes into the game on a header by Greek defender Dimitris Siovas past Spanish net minder Jordi Masip.
Valladolid tried to hit back but struggled against Leganes' five-man back line and was unable to create dangerous scoring chances despite its manager's tactical changes and the team's ball possession.
Valladolid was out-of-sorts defensively and nearly fell behind 3-0 late in the first half on a foray by Moroccan forward Youssef En-Nesyri into the hosts' area, although Masip was able to thwart that one-on-one opportunity.
Toni Villa, however, managed to pull one back for Valladolid - and score for the first time in La Liga - just five minutes into the second half, netting a goal after teammate Nacho had sent a powerful shot off the post.
The Albivioletas' joy was shortlived though as keeper Masip lost control of the ball inside his area and allowed Argentine forward Guido Carrillo to give the visitors a 3-1 lead in the 66th minute.
Valladolid's poor defensive game then continued when Carrillo took advantage of another defensive mistake to give Leganes a 4-1 lead, scoring on an unmarked header from inside the box nine minutes later.
With time winding down and the game already out of reach, Unal scored Valladolid's second goal in second-half stoppage time.
With its fourth win of the season, Leganes has provisionally climbed into the 15th spot in the Spanish-league standings with 16 points, while Valladolid is provisionally in 14th place with 17 points.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)