Thiago's opening strike was Bayern Munich's 100th goal in all competitions this season
Bayern Munich reached the Champions League quarter-finals for the seventh successive year with a thumping victory over Besiktas.
The German champions led 5-0 on aggregate after the first leg, and Thiago's early goal in Istanbul extended their advantage.
A Gokhan Gonul own goal immediately after half-time doubled Bayern's lead, before Vagner Love pulled one back.
Sandro Wagner wrapped up a comfortable win for Bayern with a tap-in.
Besiktas - the first Turkish side to win a Champions League group - fielded six players aged 30 or older.
They started stronger than Bayern but it was the visitors who had the first chance when David Alaba's free-kick was palmed low into the path of Thomas Muller, but he sliced over.
Thiago broke the deadlock with a simple tap-in from Muller's perfectly weighted cross, quelling Besiktas' early energy with his second Champions League goal of the season.
But he lasted just 35 minutes before being substituted.
Vagner Love celebrates scoring a consolation goal for Besiktas
Bayern extended their lead moments after the start of the second half when Turkey international Gonul flicked the ball into his own net from a Rafinha cross.
Besiktas improved and were rewarded when they pulled a goal back following a mistake in the Bayern defence, Love slotting into the bottom corner past Sven Ulreich for his first Champions League goal since 2011.
They could have had a second just minutes later when Mustafa Pektemek's shot from close range was deflected behind by Alaba.
But Bayern scored their third of the night with six minutes remaining when substitute Wagner chested a deflected cross into an empty net.
Sixteen become eight... This season's Champions League quarter-finalists are: Barcelona, Bayern Munich, Juventus, Liverpool, Manchester City, Real Madrid, Roma and Sevilla. The draw will take place in Nyon, Switzerland at 11:00 GMT on Friday - and you can follow it live on the BBC Sport website and app.
'It was a bit wild' - what they said
Bayern Munich captain Thomas Muller: "In the second half we were not really in control. It was a bit wild, all over the place.
"We lost possession too often, made unnecessary fouls.
"We won 3-1 away from home but somehow that second half did not feel really that good."
Bayern Munich head coach Jupp Heynckes: "It was a convincing result. Besiktas hadn't lost here in the Champions League, so it wasn't easy.
"We scored at the right times and it's normal that we dropped off a little - losing some focus after winning 5-0 is just human.
"The only negative today is that we picked up too many yellow cards."
Besiktas midfielder Oguzhan Ozyakup: "We lost our qualification chances in the first leg, so this game was just a formality.
"We want to win the Turkish Super league again and come back to the Champions League stronger next season."
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VIVA – Besiktas menjamu Bayern Munich dalam leg kedua babak 16 besar Liga Champions di Vodafone Park, Kamis dini hari WIB 15 Maret 2018. Tim tamu mengakhiri laga dengan kemenangan 3-1. Tim tamu langsung membuka keunggulan ketika pertandingan memasuki menit 18. Thiago Alcantara membobol gawang Besiktas usai menerima umpan dari Thomas Mueller. Skor 1-0 untuk keunggulan Bayern bertahan hingga babak pertama usai. Satu menit setelah babak pertama dimulai, skuat asuhan Jupp Heynckes kembali menambah keunggulan.
Kali ini bunuh diri Gokhan Gonul. Saat dia berusaha menghalau serangan, namun bola justru mengarah ke gawang Besiktas yang dikawal Tolga Zengin. Tak ingin malu di kandang sendiri, Besiktas mencoba bangkit. Hasilnya pada menit 59 mereka sukses memperkecil ketertinggalan menjadi 1-2 melalui gol Vagner Love. Bayern kembali menambah keunggulan saat pertandingan memasuki menit 84. Kali ini giliran Sandro Wagner yang membobol gawang Besiktas. Dengan hasil ini, Bayern melaju ke perempat final Liga Champions dengan keunggulan agregat 8-1. Karena pada leg pertama mereka menang lima gol tanpa balas. Susunan pemain: Besiktas: Tolga Zengin; Gary Medel, Necip Uysal, Caner Erkin, Gokhan Gonul, Mustafa Pektemek, Oguzhan Ozyakup, Tolgay Arslan (Atiba Hutchinson 60'), Vagner Love (Ryan Babel 75'), Jermain Lens (Anderson Talisca 60'), Ricardo Quaresma. Bayern Munich: Sven Ulrich; Mats Hummels (Niklas Suele 45'), Jerome Boateng, David Alaba, Rafinha, Javi Martinez, Thiago Alcantara (James Rodriguez 35'), Arturo Vidal, Robert Lewandowski (Sandro Wagner 68'), Franck Ribery, Thomas Mueller.
Bayern Munich moved into the Champions League quarter-finals after beating Besiktas in Istanbul on Wednesday to complete an 8-1 aggregate victory against the Turkish side.
It was a record 11th successive victory in the competition for their coach, Jupp Heynckes, who had led Bayern to the title in 2013 before retiring and returning this season.
Barcelona v Chelsea: Champions League – live! Read more
The Bundesliga champions went ahead through Thiago Alcântara in the 18th minute to kill off any lingering hopes of an improbable recovery by the hosts after Bayern had hammered them 5-0 in the first leg in Munich. However, the Spaniard was taken off with a suspected ankle problem a little later, having only recently returned from an injury break.
Bayern, who could secure their sixth consecutive Bundesliga title at the weekend, went 2-0 up seconds after the second-half restart when Gokhan Gonul volleyed a Rafinha cross into his own net.
Besiktas, who were missing their entire central defence, offered little resistance despite controlling possession. They did manage to pull a goal back through Vágner Love’s effort in the 58th minute which breathed some brief life into the hosts.
But the Bayern substitute Sandro Wagner chested in a David Alaba cross with six minutes remaining to confirm Bayern’s victory.
