The result kept Efes joint top of their eight-team pool in the second group stage with a 7-1 record alongside Real Madrid, after the winners of eight titles in Europe's premier club competition ground out a 77-72 home victory against Alba Berlin.
Holders Olympiakos Piraeus also stayed on course to reach the best-of-five quarter-final playoff series after an 82-74 home defeat of Spaniards Caja Laboral Vitoria, who suffered a fourth successive loss after winning their opening four games in the top 16.
Four teams from each of the two pools will progress to the playoffs, whose winners will advance to the May 10-12 Final Four in London.
Efes boosted their hopes of becoming the first Turkish team to win the Euroleague after 26-year-old Farmar nailed a crunch-three pointer and a pair of free throws to complete the his team's comeback from a 10-point deficit.
Farmar, who played for the Lakers from 2006-2010 and then the next two seasons at the New Jersey Nets, finished with 15 points. Although he struggled to get open shots in a tight contest, his late barrage cancelled out an outstanding performance by CSKA playmaker Milos Teodosic.
The Serb netted a game-high 26 points and dished out five assists but missed a difficult long-range shot from near the halfway line on the buzzer, leaving CSKA in a precarious position with a 5-3 record.
"It was a very physical game and tiny details determined the winner," CSKA coach Ettore Messina, who won two Euroleague titles with the Russian side during his first spell in charge 2005-09, told the competition's official website (www.euroleague.net).
"We had a good margin at halftime but it melted down in a very short period as we gave up too many offensive rebounds at crunch time," he said.
Real were pegged back for three quarters before pulling away in the final period to break down stubborn Alba with Jaycee Carroll, Rudy Fernandez and Nikola Mirotic scoring 42 points between them.
Caja Laboral's topsy-turvy season rolled on with a tame defeat which left the fickle Basque outfit, who squeezed into the top 16 by the skin of their teeth, with plenty of work to do if they are to reach the knockout stage.
Caja scraped through with three straight wins after losing six of their opening seven games and then got off to a flying start in the second phase with four wins on the trot, but another dip in form means they have little room for error in the remaining six matches.
Olympiakos, who had also made a patchy start, broke into the top four in their pool thanks to an effervescent performance by shooting guard Acie Law who led the way with 18 points.
Barcelona, the 2010 champions, went top of the group with a 7-1 record after a 99-60 mauling of Fenerbahce Istanbul on Thursday.
Forward Pete Mickeal buried 17 points while centre Ante Tomic and guard Marcelinho Huertas chipped in with 14 each for Barca, who stole a march on Montepaschi Siena after the Italians suffered a 92-61 drubbing at Maccabi Tel Aviv.
The Israeli side, who have four Euroleague titles, rekindled their own hopes of progressing after Yogev Ohayon and Devin Smith scored 19 points apiece to delight coach David Blatt.
"We've been through a lot lately and we couldn't put together four good quarters until tonight," said Blatt, who steered Russia to the 2007 European Championship title.
"I am happy we've managed to do that and I hope we can do it again in the upcoming games because we need to keep this momentum going."
Elsewhere, six-time champions Panathinaikos Athens earned a 78-73 success at 1999 winners Zalgiris Kaunas, their 15th win in 16 meetings against the Lithuanians who face an uphill battle to avoid an early exit.
Croatia guard Roko Leni Ukic shook off a back injury to produce his most impressive performance of the season for Panathinaikos, amassing 21 points after hitting eight of 10 shots from the field.
"It was a crazy three days for me because two days ago I had problems with my back and didn't even know if I would play," he said.
"Sometimes when you are hurt you play even better and this was one of those days. Right now we are in a very good position although we have a lot of tough games left."