Keita capped off a superb solo run to put Leipzig in front just before half-time, and the midfielder struck again on 74 minutes.
Guinea international Naby Keita scored twice as Bundesliga newcomers RB Leipzig defeated Werder Bremen 3-1 on Sunday to climb up to second place in Germany.
Keita capped off a superb solo run to put Leipzig in front just before half-time, and the midfielder struck again on 74 minutes when he powered home a cross from former Bremen striker Davie Selke.
Serge Gnabry gave the visitors hope as he cut the deficit in half almost immediately, but Germany Under-21 international Selke, who left Werder for Leipzig in July 2015, sealed the win deep into stoppage time.
Ralph Hasenhuettl's Leipzig extended their unbeaten start to their maiden campaign in the German top flight as they pulled to within two points of leaders Bayern Munich.
Werder, who lost their first four matches this term, dropped to 15th in the table after seeing a three-game unbeaten run snapped.
Schalke collected just their second win after a dreadful start to the campaign as they eased past Mainz 3-0 in Gelsenkirchen.
Algerian midfielder Nabil Bentaleb, on loan from Tottenham Hotspur, scored either side of a Max Meyer strike to fuel the Royal Blues' continued resurgence.
Reigning champions Bayern defeated Borussia Moenchengladbach 2-0 on Saturday with goals from Arturo Vidal and Douglas Costa to return to winning ways after back-to-back draws in the league.
Borussia Dortmund twice fought back from two goals behind to salvage a 3-3 draw at lowly Ingolstadt after 18-year-old US international Christian Pulisic popped up with an equaliser at the death.
Hoffenheim, like Bayern and Leipzig, also remain undefeated following an impressive 3-0 victory away to Bayer Leverkusen.