Messi guided league leader Barcelona to a 3-0 win at home over promoted Eibar, setting up Xavi Hernandez to break through in the second half and scoring after Neymar had doubled the lead.
Messi is now poised to equal Telmo Zarra's milestone of 251 goals that has stood since 1955 next week at rival Madrid's Santiago Bernabeu Stadium.
Valencia and Sevilla can both pass Madrid, which moved into a provisional second place, with wins on Sunday.
While Messi closed on Zarra, Ronaldo made sure to make his own mark by breaking a record that had stood since the 1943-44 season when Oviedo's Esteban Echevarria scored 14 goals through the first eight rounds.
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The Ballon d'Or holder opened from the penalty spot in the 13th minute before adding another goal in the 61st, increasing his league-leading tally to 15 goals in eight rounds despite missing one game due to injury.
Javier Hernandez, James Rodriguez and Francisco "Isco" Alarcon also scored to rout the overmatched hosts at Ciutat de Valencia Stadium.
Ancelotti said that Gareth Bale didn't play because of pain in his gluteus. The manager rested him as a precaution with Madrid visiting Liverpool in the Champions League on Wednesday before the first "clasico" match of the season three days later.
Elsewhere, Manuel "Nolito" Agudo continued his strong campaign by scoring in the 73rd to give Celta Vigo a 1-1 draw at Athletic Bilbao, keeping the Basque club with one win in 10 matches in all competitions not counting its elimination of Napoli from the Champions League playoffs.