Sebastian Vettel has suggested that Red Bull Racing will have things far from all its own way in qualifying for this weekend's Monaco Grand Prix, arguing that the leading four teams are too close to call around the tight, tortuous streets of the glamorous Principality.

Vettel wound up third overall at the end of the opening day of running in Monte Carlo on Thursday, with team-mate Mark Webber down in tenth - and whilst the true pecking order in practice is famously hard to accurately discern, that it is going to be a fraught battle for pole position seems assured.

That spot, of course, has been Red Bull's sole preserve in each of the five races of the campaign to-date - three times courtesy of Vettel, and the other two Webber, and in Barcelona last weekend to the tune of almost a full second clear of anybody else - but on the evidence of what has been seen so far, pole this time around could go any which way amongst the leading contenders.

"We did a lot of laps, which is good as that's important in Monaco," affirmed Vettel. "The car feels alright, but if you look at the times it's difficult to judge where we are. One thing that's clear is that it will be very, very tight over the weekend.

"The top four teams are split by a couple of tenths and fuel loads are not as important here, so it's close. It looks challenging. Qualifying has been good for us in the last races, and I hope that continues on Saturday."

Webber, for his part, remained unconcerned by his comparatively lowly spot on the end-of-day timesheets - and confident that the energy drinks-backed outfit has made great strides forward with the slow-speed form of the Adrian Newey-penned RB6, after its predecessor tended to struggle more around high-downforce circuits in the early stages of 2009.

"It was a pretty good day," underlined the Spanish Grand Prix winner. "We went a bit early with the 'Options' to beat the weather and we've got a bit of work to do with the balance, but in general it was good. We've made progress in the low-speed stuff since last year.

"We saw indications of it in Singapore and Abu Dhabi, and what we learned with the RB5 has rolled into the RB6. It will be tighter here than it was in Spain; it's a special track - we know that. Saturday will be an exciting qualifying session, for definite."