The 2009 world champion, who signed a new deal with the Woking-based team this week, led a McLaren one-two in the first session, before taking almost two seconds off his best run as he maintained his position at the top of the timesheets with a time of one minute 31.901s.
Button is still looking for his first victory in Suzuka, and the McLaren cars certainly looked impressive in the first session – but Lewis Hamilton could only manage eighth quickest in the second session.
â€œItâ€™s always fun driving around Suzuka, particularly when you have a good car beneath you,â€ Button said.
â€œThis is an amazing circuit, the first sector is phenomenal – there is no rest, I donâ€™t think you breathe through that whole sector.
“Itâ€™s all about getting it together and finding a balance that lets you flow through there. And the car feels good around here.
â€œI donâ€™t really know what to take from today in terms of where we stand, but the car feels pretty good.â€
Ferrariâ€™s Fernando Alonso was second quickest, 0.174s adrift of Button, with Vettel recovering from a mistimed approach to Degner One, which saw him ran wide across the gravel trap before coming to a stop against a tyre barrier at Degner Two to take third quickest for Red Bull in the second session.
Mark Webber was fourth quickest in the second Red Bull, while Ferrariâ€™s Felipe Massa was a half second down, but ahead of Mercedes duo Michael Schumacher and Nico Rosberg.
McLaren will conduct an inquiry into why Hamilton was 1.344s slower than his team-mate, and just ahead of Renaultâ€™s Vitaly Petrov and Toro Rossoâ€™s SÃ©bastien Buemi who rounded out the top 10, after being as competitive in the first session.
Williamsâ€™ Rubens Barrichello was the most notable casualty in the second session as he slammed into the tyre barrier after also running wide at Degner One, with the second FW33 of Pastor Maldonado suffering a mechanical fault to leave the struggling Grove-based team 17th and 21st respectively.
Renaultâ€™s Bruno Senna was another too late on his brakes, his incident coming into the aptly named First Curve, but the Brazilian narrowly avoided a barrier after sliding across the gravel, before being pushed back on to the track with the aid of some helpful marshals.
Force Indiaâ€™s Paul di Resta was a disappointing 15th, languishing 2.7s behind Button, and 0.8s off his team-mate Adrian Sutilâ€™s time, despite the German sitting out the first session.
Hispania’s Vitantonio Liuzzi will have his work cut out in Saturday morningâ€™s final practice session to get within the 107 per cent qualifying time after a mechanical problem reduced the Italian to just four completed laps, his best 10.5s slower than Button.
1 Jenson Button McLaren-Mercedes 1m31.901s 32 laps
2 Fernando Alonso Ferrari 1m32.075s + 0.174 33 laps
3 Sebastian Vettel Red Bull-Renault 1m32.095s + 0.194 35 laps
4 Mark Webber Red Bull-Renault 1m32.147s + 0.246 28 laps
5 Felipe Massa Ferrari 1m32.448s + 0.547 34 laps
6 Michael Schumacher Mercedes 1m32.710s + 0.809 26 laps
7 Nico Rosberg Mercedes 1m32.982s + 1.081 27 laps
8 Lewis Hamilton McLaren-Mercedes 1m33.245s + 1.344 26 laps
9 Vitaly Petrov Renault 1m33.446s + 1.545 36 laps
10 Sebastien Buemi Toro Rosso-Ferrari 1m33.681s + 1.780 33 laps
11 Jaime Alguersuari Toro Rosso-Ferrari 1m33.705s + 1.804 25 laps
12 Adrian Sutil Force India-Mercedes 1m33.790s + 1.889 36 laps
13 Sergio Perez Sauber-Ferrari 1m34.393s + 2.492 35 laps
14 Bruno Senna Renault 1m34.557s + 2.656 27 laps
15 Paul di Resta Force India-Mercedes 1m34.601s + 2.700 33 laps
16 Kamui Kobayashi Sauber-Ferrari 1m36.038s + 4.137 33 laps
17 Heikki Kovalainen Lotus-Renault 1m36.225s + 4.324 35 laps
18 Rubens Barrichello Williams-Cosworth 1m37.123s + 5.222 14 laps
19 Timo Glock Virgin-Cosworth 1m37.440s + 5.539 30 laps
20 Jerome D’Ambrosio Virgin-Cosworth 1m38.093s + 6.192 30 laps
21 Pastor Maldonado Williams-Cosworth 1m38.387s + 6.486 16 laps
22 Daniel Ricciardo HRT-Cosworth 1m38.763s + 6.862 36 laps
23 Jarno Trulli Lotus-Renault 1m39.800s + 7.899 24 laps
24 Tonio Liuzzi HRT-Cosworth 1m42.480s + 10.579 4 laps
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