Pep Guardiola's side eased to a 5-0 win over Sparta Prague, while the Reds nullified the threat of their hosts RB Leipzig and earned a 1-0 win in Germany. A day prior, both Aston Villa and Arsenal had secured victories over Bologna and Shakhtar Donetsk respectively.
The midweek results has seen three Premier League sides are the summit of the new-look Champions League table, with Unai Emery's side topping the standings thanks to their superior goal difference over Liverpool.
The Midlands club and the Reds are the only two sides in this year's competition with 100 per cent records, while City are the best of the teams on seven points.
The 2023 winners, like Villa, are still yet to concede in the competition this season. Arsenal, who are down in ninth place, are another outfit boasting a perfect defensive record along with Inter Milan and Atalanta.
Liverpool kept up their perfect start with a 1-0 win over Bundesliga high-flyers RB Leipzig
In fact, the only player to score against an English team in the competition so far is former Chelsea winger Christian Pulisic, who netted for AC Milan in their 3-1 defeat by Liverpool last month.
The league phase, introduced for the first time this season, sees all 36 teams ranked in one table, with the top-eight sides progressing to the last-16 after eight matches.
Teams finishing in positions nine to 24 will be drawn together in a play-off, with the victors joining the automatic qualifiers in the next round.
The Premier League side's strong showing so far is also highlighted in their unbeaten records. Of the nine teams yet to lose in the competition, four are from the English top-flight.
The only other nations to have at least two unbeaten clubs are France - with the surprising pair of Monaco and Champions League debutants Brest - and Italy.
Bayer Leverkusen, Inter, Atalanta and Sporting CP are the other sides yet to taste defeat in the European Cup this term.
The next round of fixtures on November 5 and 6 sees City travel to Portugal to face Sporting, while Liverpool welcome their former player Xabi Alonso and his Leverkusen side to Anfield.
Villa, meanwhile, will be confident of maintaining their perfect start when they face Cub Brugge in Belgium, while Arsenal face the hardest test with a trip to San Siro to take on the Serie A champions Inter.