In this study, we examine connective protest mobilization and suppression during the 2021 protests in Russia. We use time series analysis to study the dynamic interplay between the pro-Navalny movement and pro-government countermovement on Twitter, complemented by network analyses of co-retweeting networks to assess the movements’ coordination patterns. Findings show that pro-Navalny accounts were more active and coordinated within more centralized Twitter networks than pro-government accounts. Contrarily, the pro-government camp employed preventive communication tactics and coordinated in more clustered networks. Granger causality tests reveal that pro-Navalny tweeting activity triggered increased pro-regime reaction during the largest protests on 23 January and 21 April, whereas pro-government tweeting activity caused the escalation of pro-Navalny reaction during the 14 February protests. Both sides’ tweeting activity decreased after the February protests, presumably due to external repression. These findings contribute to a deeper understanding of online mobilization and coordination strategies via social media in authoritarian contexts.