Lech Poznan scored two late goals — one freakish and the other superb - to stun Manchester City 3-1 while Juventus drew 0-0 with Salzburg for their fourth draw in as many group games.
Russian pair CSKA Moscow and Zenit St Petersburg qualified for the knockout rounds and maintained their 100 percent records, the former beating visitors Palermo 3-1 and the latter winning 3-2 at Hajduk Split.
BATE Borisov, Porto and VfB Stuttgart also went through. Sampdoria's goalless draw at home to Metalist Kharkiv meant Italy's four representatives failed to win a game between them for the second time in a row.
Liverpool, still unbeaten in Europe this season, were in danger of losing that record when Argentine Ezequiel Lavezzi burst clear to give Napoli a halftime lead at Anfield.
But a weak back pass by ex-Liverpool defender Andrea Dossena allowed halftime substitute Gerrard to level in the 76th minute.
The England midfielder converted a penalty two minutes from time after Glen Johnson fell under Salvatore Aronica's challenge and completed his hat trick 60 seconds later when Lucas sent him clear to dink the ball over keeper Morgan De Sanctis.
The win kept Liverpool top of Group K with eight points from four games, three ahead of Steaua Bucharest who beat Utrecht 3-1.
Group F leaders CSKA Moscow scored three times in seven minutes after halftime to sink Palermo, with Japan midfielder Keisuke Honda wiping out Massimo Maccarone's 10th minute effort for the visitors before Tomas Necid added two more.
Zenit, who top Group G, took a first half lead through Aleksei Ionov before Szabolcs Huszti and Alessandro Rosina converted penalties after the break. Marin Ljubicic and Ante Vukusic's late replies were not enough for the Croatians.
Bundesliga bottom side Stuttgart continued to shine in Europe as they won 3-0 at Getafe to maintain their 100 percent record in Group H and qualify, with Ciprian Marica, substitute Timo Gebhart and Martin Harnik sharing the goals.
Bate's Aleksandr Pavlov and Renan Bressan scored in the last 20 minutes to help Group E leaders BATE to a 3-1 win over Sheriff Tiraspol.
It was an unhappy European debut for the Moldovan team's 19-year-old goalkeeper Dmitri Stajila who replaced the injured Vladislav Stoyanov just before the hour.
Porto made sure of qualifying despite dropping their first points in Group L in a 1-1 home draw with Besiktas.
Lech reclaimed top spot in Group A on goals scored after beating Manchester City, the world's richest club, with both teams now on seven points from four games.
Dimitrije Injac fired the Poles ahead and, although Emmanuel Adebayor equalized after halftime, Lech went back in front with four minutes left when City defender Dedryck Boyata's headed clearance hit Manuel Arboleda on the head and went into the net.
Four minutes later Lech's 19-year-old substitute Mateusz Mozdzen added to City's misery with a superb curling shot into the top corner from almost 25 meters.
Juventus, who host City in their next game, have four points after failing to break down the Austrian champions at home.
Atletico Madrid's Tiago scored a stunning winner six minutes from time to give the holders a 2-1 win at Rosenborg in Group B, with the midfielder leaving three players in his wake before a long-range strike gave goalkeeper Daniel Orlund no chance.
Sergio Aguero had put Atletico ahead after four minutes before Rosenborg, newly-crowned Norwegian champions, equalized through Markus Henriksen after halftime.
Atletico have seven points in Group B, one behind leaders Bayer Leverkusen who beat Aris Salonika 1-0.
