It's fair to say that this morning's final practice session only served to further confuse matters.
While Nico Rosberg closed the gap to teammate Lewis Hamilton, both were out-paced by Max Verstappen, the German finishing fourth behind Ricciardo also.
Indeed, Rosberg's pace is one of the big mysteries, he has been consistently off his teammate's pace in all three sessions, but is this genuine or is he merely keeping his powder dry. Then again, with a 26 point advantage, the onus is on Hamilton.
Ferrari didn't quite carry over the pace from yesterday, though both were within 0.8s of Verstappen's pace.
Both Williams were in the mix, particularly Valtteri Bottas, while local hero Sergio Perez was out-paced by his Force India teammate. Indeed, the Silverstone outfit was under pressure from a revived Toro Rosso.
The plain fact is that grip is an issue with everyone struggling on all the compounds. Another major factor, and one which will play a part in Q1, is traffic.
Though the soft and supersofts are seeing drivers improving their times on their second flying laps, the traffic, particularly in the Stadium, are negating those potential improvements.
Consequently it is still wide open, though surely few would bet against Mercedes and in particular Hamilton.
A driver already worried about his place on the 2017 grid is destined to start from the back of the grid tomorrow, Renault revealing that Jolyon palmer will not take part in this session after damaging his chassis this morning.
"I won't be taking part in Quali after we found a crack in the chassis," confirmed the Briton. "Big shame as we were 14th in FP3 and aiming for Q2 again."
Air temperature has increased to 17 degrees C, while the track temperature is 47 degrees. It remains cool but nice and sunny.
The lights go green and Gutierrez leads the way, followed by Ericsson, Magnussen, Grosjean and Wehrlein. All are on supersofts.
Gutierrez reports that his tyres are not ready for a flying lap on what would have been his first flying lap, he is informed that Grosjean has reported a similar issue. Indeed, the Frenchman posts 27.544 and Gutierrez 29.430, while Kvyat goes quickest with a 21.454.
A mistake as he enters the Stadium sees Grosjean fail to improve, he heads back to the pits.
The crowd erupts as Perez heads out, meanwhile Sainz posts 21.100 to take the top spot. However, he loses time behind Sainz who is on his cool down lap.
Button goes third (21.561), as Perez posts 28.341, again the tyres not up to it on the first flying lap.
That said, on his first flying lap Hamilton goes quickest in the first two sectors, finally crossing the line at 19.970 to demote Hulkenberg.
Perez improves to second but he and Hamilton are then demoted when Vettel posts 19.865 to go quickest.
A 19.554 sees Raikkonen go top, as Verstappen goes third and Ricciardo fifth.
Rosberg can only manage seventh, the German stopping the clock at 20.396.
"I've got no power," reports Kvyat now down in 15th. "OK, bring her back then."
Rosberg improves to sixth (19.996) having gone quickest in the second sector. However, Ricciardo crosses the line at 19.713 to split the Ferraris.
Going quickest in the two final sectors, Hamilton posts 19.447, eclipsing Raikkonen by 0.107.
A massive lock-up for Bottas as he seeks - and obviously fails - to improve on eighth.
With under four minutes remaining, Ericsson, Grosjean, Nasr, Ocon and Gutierrez comprise the drop zone. Another poor session for Haas.
Toro Rosso reveals that Kvyat's issue is terminal, he will play no further part in qualifying. He is currently sixteenth, just outside the drop zone.
Gutierrez improves to fifteenth with a 21.401 but is it enough?
Ericsson also improves, the Swede going twelfth with a 21.062, which pushes Button down to fifteenth.
Ocon can only manage 21.881 which puts him 19th, but he is dmoted when Nasr posts 21.692.
A mistake sees Gutierrez spin at T9, the Mexican right on the cusp in 16th.
A late charge sees Wehrlein post 21.363 to take sixteenth, thereby demoting Gutierrez
Quickest is Hamilton, ahead of Raikkonen, Ricciardo, Vettel, Verstappen, Rosberg, Perez, Bottas, Masa and Sainz.
The top six are covered by just 0.549.
We lose Gutierrez, Kvyat, Nasr, Ocon, Grosjean and Palmer.
Check out our Saturday gallery from Mexico City, here.
sign in