Neymar opened the scoring in the 25th minute with a splendid curled shot from outside the area that went into the top corner.
A sharp counter-attack then led Mbappe to play through Neymar, who doubled the French champions’ lead with a cross shot in the 38th.
Mbappe made it 3-0 three minutes before the break with a penalty awarded after keeper Mert Gunok had brought down Neymar. Mitchel Bakker had followed up and tapped in but he was ruled offside following a VAR review and referee Danny Makkelie gave PSG the spot-kick.
France striker Mbappe, 21, became the youngest player to score 20 goals in the Champions League.
Neymar, who has scored six goals from five appearances in the competition this season, added the fourth five minutes into the second half with a powerful strike from just inside the area.
Basaksehir, who had drawn two and lost three of their last five competitive games, had little to offer but they reduced he arrears in the 57th thanks to a powerful Mehmet Topal volley.
But PSG restored their four-goal advantage when Mbappe, who had not netted in his nine previous Champions League appearances, tapped in from Angel Di Maria’s pass on 62 minutes.
Basaksehir, who were eliminated from all European competitions before kick-off, finished bottom of the group with three points.
Third-placed Manchester United will play in the Europa League last 32 after picking up nine points.
In other results Thursday (AEDT), Socceroo Awer Mabil’s Champions League campaign is over though his Danish side FC Midtjylland can hang their heads high after holding six-time European champions Liverpool to a 1-1 draw.
Champions League matchday 6 results
- Zenit 1 Dortmund 2
- Lazio 2 Club Brugge 2
- Barcelona 0 Juventus 3
- Chelsea 1 Krasnodar 1
- RB Leipzig 3 Manchester United 2
- Dynamo Kyiv 1 Ferencvaros 0
- Rennes 1 Sevilla 3
- Midtjylland 1 Liverpool 1
- PSG 5 Istanbul Basaksehir 1
- Ajax 0 Atalanta 1
Mohamed Salah became Liverpool’s all-time top scorer in the Champions League when he put the Premier League champions ahead in the first minute, latching on to a poor backpass and bursting goalwards before slipping the ball past goalkeeper Jesper Hansen.
The goal was Salah’s 22nd in the Champions League.
The Danes drew level in the 62nd minute through an Alexander Scholz penalty after Liverpool keeper Caoimhin Kelleher brought down Anders Dreyer. The linesman had initially flagged for offside but that decision was overturned by VAR.
A late goal from Luis Muriel earned Atalanta a 1-0 win at 10-man Ajax Amsterdam on Wednesday and sent the Italian side into the Champions League knockout stages at the expense of their Dutch hosts.
Ajax needed victory at the Amsterdam Arena to pip their Italian visitors to second place in Group D behind Liverpool but failed to create many chances as Atalanta produced an astute performance topped off by a breakaway goal in the 85th minute.