Marcelo Oliveira's men are three points clear on top of the Brazilian top flight table, after finally breaking clear of their 14th-placed opponents having blown two first-half leads.
Willian got the Estadio Governador Magalhaes Pinto hosts off to a brilliant start, netting a first-minute goal.
But the visitors were up for a fight, and Willie got the first of his brace in the 18th minute.
Cruzeiro steadied with two goals in seven minutes, as Lucas Silva and Julio Baptista beat Vasco shot-stopper Diogo Silva.
But Vasco went to the interval level, as Andre tucked away their second - from Fagner's second assist of the contest - before Willie struck in the 43rd minute to restore parity at 3-3.
A tense battle ensued after the break, and it took another 22 minutes for the game's seventh goal - as Lucas Silva's second gave Cruzeiro breathing space.
And the three points were secure when Vinicius Araujo was on target, although Cruzeiro's night was slightly soured by the dismissal of second-half substitute Dagoberto on 90 minutes.
Second-placed Gremio made it five league wins in succession on Saturday, with a 1-0 triumph over 10-man Ponte Preta.
Striker Giovanni was given his marching orders for a second yellow in the 54th minute, and six minutes later, Kleber scored the game's only goal.
Atletico PR made it three wins in a row to climb into third after thrashing Nautico on the road 4-1.
Leo and Everton scored early for Atletico, before Ederson's late brace made sure of the points.
Botafogo slipped to fourth after playing out a 0-0 draw with Sao Paulo.
Corinthians were powered to a 4-0 win over Flamengo on the back of an Alexandre Pato brace, with the three points leaving them in fifth - one point behind Botafogo.
Portuguesa shot out of the blocks to a 3-0 lead inside seven minutes before holding on for a 4-2 win over Bahia - although the result could not help them escape the drop zone.
Santos enjoyed back-to-back wins with a 2-0 triumph away at Fluminense, who are only two points from the drop.
Goias and Coritiba failed to score in their respective home matches against Atletico Mineiro and Internacional respectively, with both matches 0-0.
Criciuma have won three of their past four matches in the league, most recently posting a 1-0 result away at Vitoria - who have lost three straight.
Get the best features, fun and footballing frolics straight to your inbox every week.