This morning's final practice session posed more questions than it answered, with Fernando Alonso edging out Daniel Ricciardo for top honours.

Nico Rosberg was third quickest and Mercedes teammate Lewis Hamilton, who was quickest yesterday, down in sixth.

While some say Mercedes is merely 'keeping its power dry' others wonder if the characteristics of the Singapore circuit have allowed Red Bull and Ferrari to close in.

Hamilton, in particular, wasn't happy this morning, the Briton having a big moment after his car stalled mid-lap, though he was able to sort it pretty quickly.

At the end of the session Rosberg didn't appear too happy either and was seen in deep 'animated' conversation with Toto Wolff and Paddy Lowe, though the Austrian was giving little away.

Without doubt Singapore is one of the toughest races on the calendar, on the drivers and cars, and for once we could see Mercedes under some real pressure.

Again, there is a clear performance gap between the two Ferraris while the Williams duo finally began to show their cards this morning.

Also very much on the pace is the Toro Rosso pair, whilst McLaren was disappointing, though not as bad as Lotus.

The top seven - Alonso, Ricciardo, Rosberg, Vergne, Vettel, Hamilton and Massa - were covered by just 0.610s.

Being a street circuit a good grid position is vital though, as we know from experience, safety cars are a regular item here.

In yesterday's second session there was real uniformity with McLaren, Force India, Toro Lotus and Sauber behind the main front runners, but that all appeared to go out the window this morning. Lotus will be lucky to scrape into Q2 whilst McLaren will do well to get both cars into Q3.

Then again, over enthusiasm from almost anyone in Q1 could cause problems even for the big guns in terms of yellow flags, or even red, while the 2+ second gap between the two compounds could cause problems with some of the big boys forced to use a set of options earlier than they would like.

As we await the start of Q1, the air temperature is 27 degrees C, while the track temperature is 33 degrees. Humidity is 77%.

Kvyat and Vergne are among the first out, with Rosberg another 'early bird'.

Hamilton is advised that he is using new brakes.

Shades of Monza - and Monaco - as Rosberg takes to the escape road at T8 after locking up on his first flying lap. Is he also running new brakes?

Of the first wave, Bottas goes quickest, ahead of Vergne, Hulkenberg, Button and Perez. Hamilton posts 2:02.007 before improving to 1:58.238 to go twelfth.

On his second flying lap Rosberg posts 48.775 to go second but is subsequently demoted when the Ferrari duo go 1-2, Alonso posting 48.203.

Despite another scrappy lap, Hamilton goes quickest with a 47.847, almost a second quicker than his teammate.

"I have a problem with the braking," says Grosjean as teammate Maldonado heads off into the escape road at T7.

Gutierrez, using the option rubber, goes second with a 47.970, a clear sign that the big boys will also have to make the switch sooner than they wished.

As Rosberg almost trips up over Kvyat and Ericsson, much to the German's obvious frustration, the Mercedes duo switch to options.

With 4:06 remaining all are on options.

Hulkenberg goes quickest with a 47.370, thereby dropping Button into the drop zone. Vettel and Ericsson yet to post a time.

Ricciardo goes second with a 47.488 only to be demoted when Raikkonen posts a 46.685 to go quickest.

Button goes second (47.161) and Vettel fifth (47.476).