Ahead of today's all-important qualifying session, the air temperature is 28 degrees C, while the track temperature is 32 degrees.

Thus far, Red Bull has been quickest in all three sessions, Daniel Ricciardo in both yesterday and teammate Max Verstappen this morning. It's entirely possible the Australian could have made it a hat-trick but a brush with the unforgiving walls put an end to that.

After a disappointing show yesterday, Ferrari raised its game earlier, at least in the case of Sebastian Vettel, while Lewis Hamilton, despite his car looking a real handful, finished third this morning in a session which saw the top three covered by just 0.142.

Just 24 hours after breaking up with Honda, McLaren saw its two drivers finish fourth and fifth, ahead of a Red Bull, a Ferrari and a Mercedes, prompting thoughts of a nightmare scenario whereby the Japanese manufacturer comes good when its all too late for the Woking team.

Nico Hulkenberg gave another typically dogged performance earlier, while the Pink Panthers finished tenth and eleventh.

At the other end of the timesheets, Williams and Haas are clearly struggling.

The very nature of the track means the pole is important here, and few would bet against at least one Red Bull sitting on the front row tomorrow.

On the other hand, with drivers struggling for grip, which has led to numerous lock-ups and brushes with the walls, the next hour could spring some major surprises.

"Ultrasoft is around a second faster than supersoft so far," says Pirelli. "Soft could also be an interesting race tyre."

Wehrlein gets things underway, followed by Kvyat, Raikkonen and Stroll, all on the ultrasofts.

Raikkonen crosses the line at 44.060, while Kvyat is the second driver to post a time (45.628).

Grosjean runs wide in T7 and heads down the escape road.

A 44.680 sees Vettel go second, 0.620s off his teammate's pace, as the Bulls head out.

Indeed, all bar the Mercedes duo are on track.

Sainz goes third (45.203), ahead of Kvyat, Magnussen and Stroll.

Again Grosjean gets it wrong at T7.

Going very, very wide in the final corner, Alonso crosses the line at 44.120 to go second, with teammate Vandoorne going quickest (44.008) moments later.

It's fast and furious as Verstappen posts 43.031 only to be eclipsed by his teammate who crosses the line at 42.846.

Vettel improves with a 43.336 to go third but is demoted when Hamilton posts 42.884 to split the Red Bulls.

Massa heads back to the pits with a broken wheel having clouted the wall at T21. It's not clear how bad the damage is, but we may well have seen the last of the Williams for today.

Verstappen retakes the top spot with a 42.010 as Ricciardo improves but remains second on 42.063.

Ocon clouts the wall at T21 but appears to have got away with it.

Hamilton goes third (42.455) and Bottas fourth (43.137), as the clock counts down to 4:00. Currently Wehrlein, Stroll, Massa, Grosjean and Ericsson comprise the drop zone.

Lots of smoke from the rear of Kvyat's car as he heads into the pits but his deal doesn't appear to be too concerned.

Despite a butt-clenching encounter with the wall at T21, Grosjean improves to tenth with a 43.766.

Raikkonen has leapfrogged his teammate with a 43.328.

With just over a minute remaining, Massa is back on track.

Sainz goes quickest in S1, finally crossing the line at 42.176 top go third, thereby dropping Stroll back into the drop zone.

Masa goes 15th with a 44.014, thereby demoting Hulkenberg.

Palmer goes sixth with a 42.472 as the track is now changing by the second.

Alonso goes third and Hulkenberg ninth, which is bad news for Magnussen and Massa.

Quickest is Verstappen, ahead of Ricciardo, Alonso, Sainz, Vandoorne, Hamilton, Palmer, Kvyat, Hulkenberg and Bottas.

We lose Magnussen, Massa, Stroll, Wehrlein and Ericsson.

The big guns of Mercedes and Ferrari are first out for Q2, followed by the Toro Rossos.

Raikkonen posts a 40.999 with Hamilton posting 41.075 moments later.

However, Vettel responds with a 40.529 as Bottas posts 41.409.

Game on!

All eyes on the Red Bulls as Verstappen posts 40.379 and Ricciardo 40.776.

A 41.227 sees Vandoorne go sixth, ahead of Bottas, while Alonso posts 42.242 to go ninth.

Hulkenberg goes eighth with a 41.647, while Grosjean is the only driver yet to post a time.

Ahead of the final run, it's Verstappen, Vettel, Ricciardo, Raikkonen, Hamilton, Vandoorne, Bottas, Hulkenberg, Sainz and Palmer.

With 3:33 remaining, they begin to head out, the top seven appearing to have settled... that is until Raikkonen heads out, followed by Verstappen and Hamilton. Only Vettel appear to be staying put, until he too drives out of his garage. All 15 drivers are on track... even Grosjean.

Raikkonen goes quickest in S1, as Alonso goes 8th with a 41.442.

Sainz improves to tenth, as Hulkenberg goes seventh.

Raikkonen goes second with a 40.525 as Perez complains about his tyres as he fails to improve. "I'm fed up with this ****," echoes a similarly unhappy Kvyat.

Verstappen consolidates his top spot with a 40.332 as Raikkonen goes second (40.385) and Vettel fourth (40.529).

Quickest is Verstappen, ahead of Ricciardo, Raikkonen, Vettel, Hamilton, Vandoorne, Hulkenberg, Bottas, Alonso and Sainz.

So, the Force Indias out and both McLarens through to Q3.

Check out our Saturday gallery from Singapore, here.