Although Jenson Button feels McLaren have closed up on Lotus, he says they won't really know until Saturday's qualifying.
The Brit showed some solid pace in Friday's practices for the Korean Grand Prix, finishing fifth in the morning and ninth in the afternoon.
In the latter session he was 1.101s adrift of Lewis Hamilton's P1 time but only two-hundreds of a second short of Lotus' Kimi Raikkonen.
"The circuit is always very tricky, particularly at the start of the weekend; I don't think it's used at any other time of the year so it's always very slippery in first practice," said Button.
"However, I think our afternoon session was a little more representative of our overall pace.
"We got some reasonable mileage under our belts and, even though I didn't get the best from the supersoft tyre on my fastest lap, I think we've begun to understand the characteristics of each tyre pretty well."
In fact Button even reckons McLaren have closed up on those ahead.
"In terms of performance, I think we might be a little bit closer to the Lotuses than we've been for the last couple of races - but let's see what tomorrow brings.
"Also during FP2, my mechanics needed to effect a quick fix to a brake adjuster switch inside my cockpit - the lever was adjusting itself under braking, so we had to tape it still. It had a very minor impact on my running."