In the wake of the second pre-season test at Barcelona, many believed that Ferrari had used an element of sandbagging - the practice of holding back, not showing your rivals your full strength.

This was mainly based on the fact that on a number of their fastest laps both Sebastian Vettel and Kimi Raikkonen had eased off not only visually but audibly, posting a good time but clearly having even more in reserve.

Though the Italian team vehemently denied this, as early as Melbourne it was clear that Ferrari had indeed taken a huge step forward and was now ready to take the fight to Mercedes.

From Melbourne to China and then Bahrain, over the course of the sessions that mattered, the pendulum has swung back and forth.

In qualifying in Bahrain, in particular, Mercedes appeared to find something extra, its drivers locking out the front row for the first time this season, leaving Vettel almost half-a-second adrift.

With Ferrari domination in FP1 and FP2 in Sochi, and this time both Mercedes over 0.6s off the pace, Sebastian Vettel claimed the German outfit is sandbagging as it prepares to pull out all the stops again in qualifying.

Asked if he thought Mercedes was holding back he grinned and admitted: "Yes. I think they will be fine. It's a circuit that suits them so they will be strong tomorrow.

"Last year people expected Williams to be fastest after Friday, if I remember right," he added, the German a keen F1 historian and statistician, "and it turned out Mercedes was the fastest. That's how sometimes you can be misled and I think there's a lot of things we can play within the car, fuel loads, engine modes.

"This looks like a Mercedes track," he insisted. "For sure they didn't show everything today and they didn't get a lap together, so the gap you see is artificial."

Not so, claims Hamilton.

"We never sandbag," he told reporters. "There's no benefit to sandbagging, ever.

"I think Ferrari has done in the past," he continued, "but there is zero benefit for us to do so. We're trying to get the car to the optimum balance-wise and today's generally been a tricky day. I don't know why he would suggest that... it's just Sebastian trying to blow smoke our way. Really, those guys are just very quick.

"If we get our tyres working properly I think we can be closer," he concluded. "There's no difference compared to the previous races, the gap is still very, very close between us."

Check out our Saturday gallery from Sochi, here.