Palacio grabs winner for Inter Milan
Palacio (88) nodded home from a Diego Milito cross less than a minute after Lazar Markovic had a shot saved by Samir Handanovic at the other end, sending Inter joint top of Group H on seven points.
Inter share their lead with Rubin Kazan, for whom Alan Kasaev's 16th-minute goal proved enough to see off Azerbaijan side Neftci in Russia. Inter and Kazan now hold a six-point advantage over their group rivals.
Elyaniv Barda also headed a late winner as Genk stayed unbeaten at the top of Group G after coming from behind to see off Sporting Lisbon 2-1 in Belgium.
Stijn Schaars put Sporting ahead on eight minutes, but Benjamin De Ceulaer equalised after 25 and Barda struck with three minutes to go after Sporting's Khalid Boulahrouz was sent off for a second bookable offence.
And Hungarians Videoton also continued their excellent form in the group with a 2-1 win over Basle. A Fabien Schar own goal paved the way for the hosts, who extended their lead through Marco Caneira before Schar scored at the right end in injury time.
A Lisandro Lopez opener was cancelled out by Ibai Gomez before Jimmy Briand struck the winner four minutes from time.
First half goals from Ladislav Krejci, Vaclav Kadlec and Ondrej Svejdik helped Sparta Prague to a 3-1 win over Ironi Kiryat Shmona, for whom Shimon Abuhatzira replied late on.
Lyon lead the group on nine points with Sparta clear in second on six.
Substitute Jose Toche grabbed an injury time equalizer as Panathinaikos drew 1-1 with Lazio in Group J. An own goal from Giourkas Seitaridis looked set to give the Italians the points before the late drama.
Lazio remain unbeaten on five points with Maribor in second, but all four sides are still in the running.
Late goals from Bonfim Marlos and Cleiton Xavier gave Ukrainians Metalist a 2-1 win at Rosenborg in Group K, after the Norwegians had led through Tarik Elyounoussi's 46th-minute strike.
But Metalist still conceded top spot in the group to Bayer Leverkusen, whose crushing 4-0 win at Rapid Vienna took them first on goal difference. Philipp Wollscheid, Karim Bellarabi and two from Gonzalo Castro did the damage.
In Group L, Hannover stayed top after a dramatic 2-1 win at Helsingborg, Mame Biram Diouf opening the scoring for the Germans with Alvaro Santos equalizing in injury time, only for Didier Ya Konan to restore Hannover's advantage in the third minute of added time.