The Turks went into the game looking to claw back a 1-0 first leg deficit but Arslan scored the only goal of the game at the Ataturk Olympic Stadium and then, following a goalless half hour of extra-time, struck the decisive penalty before Dejan Lovren blazed his effort for Liverpool over the bar.
With a tough clash against Manchester City in the Premier League at Anfield on Sunday, it was the nightmare scenario for Liverpool manager Brendan Rogers.
Not only did they play an energy-sapping 120 minutes of football but also had the mentally draining penalty shoot-out and a morale-sagging defeat to contend with before making the long trip home from Istanbul.
Besiktas had levelled on aggregate in the 72nd minute with a stunning strike from Arslan, assisted by a deft back heel from Senegalese striker Demba Ba, who had been the scourge of Liverpool last season when his goal, following a slip from Steven Gerrard, set Chelsea on the way to a 2-0 win at Anfield that wiped out the Reds’ advantage over eventual champions Man City in the league.
With penalties level on 4-4 after all the takers had held their nerve, Arslan deftly slotted in. Lovren stepped up for Liverpool but his effort went high, leaving Besiktas fans running onto the pitch in joy.
Title-holders Sevilla are also through to the last 16 following a 3-2 win at Borussia Moenchengladbach on Thursday.
Machin Vitolo scored a brace as the Spanish La Liga side earned a 4-2 aggregate win after winning the first leg 1-0 in Andalusia.
Borussia didn’t go quietly, though, twice fighting back from a goal down — Martin Stranzl’s own goal opened the scoring — through Granit Xhaka and Thorgan Hazard before Vitolo’s second ensured there would be no dramatic turnaround for the Germans.
– Spurs gamble scuppered –
Mauricio Pochettino’s gamble on resting several first-choice players, including star striker Harry Kane, backfired as the Tottenham Hotspur crashed out against Fiorentina.
With one-eye on Sunday’s League Cup final against Chelsea, Pochettino had made seven changes to the team that started against West Ham last Sunday.
Veteran German forward Mario Gomez and Mohamed Salah scored the goals as La Viola won 2-0 on the night in Florence to progress 3-1 on aggregate.
But it could have been so different had it not been for a glaring miss by Kane’s replacement, Spaniard Roberto Soldado in the first half, before Fiorentina’s second half goals.
Soldado raced onto a lovely through ball from Erik Lamela with Nacer Chadli joining him in escaping a faltering offside trap.
Two-on-one against goalkeeper Neto, Soldado badly underhit his pass to Chadli, allowing the Fiorentina stopper to snatch the ball and prevent a goal.
Everton are the only English side remaining in the competition after completing a crushing victory over Young Boys.
Having hit a hat-trick in the 4-1 win in Switzerland last week, Belgium forward Romelu Lukaku scored two more in a 3-1 victory at Goodison Park that secured a 7-2 aggregate success.
Roma went through 3-2 on aggregate after a 2-1 win at Feyenoord in a match that was twice stopped by the referee — coming after the vandalism committed by Feyenoord fans in Rome last week, it was another blot on the game.
The first time came just before the interval when a plastic banana was thrown onto the pitch in the direction of some Roma players.
Then, after Mitchell te Vrede was dismissed soon before the hour mark, Feynoord fans hurled projectiles onto the pitch and the referee took the players off the field for 15 minutes.
Goals from Adem Ljajic and Gervinho either side of Elvis Manu’s equaliser saw the Italians through.
Fredy Guarin struck a late winner for Inter Milan as Roberto Mancini’s men qualified for the last 16 with a 4-3 aggregate victory over 10-man Celtic, for whom Virgil Van Dijk was dismissed.
It was a good day for Italians as Napoli and Torino ousted Trabzonspor and Athletic Bilbao respectively.
Zenit Saint-Petersburg completed a comfortable victory over PSV Eindhoven, as did Ajax against Legia Warsaw.
Villarreal defeated Salzburg while Dinamo Moscow and Dynamo Kiev progressed at the expense of Anderlecht and Guingamp respectively.
VfL Wolfsburg saw off Sporting Lisbon, Club Brugge knocked out AaB and Dnipro overcame Olympiakos.