In contrast to the F1 world championship, which is over and done with despite three races remaining in the 2013 season, the title battles in the GP2 and GP3 series have come all the down to the season finale - with the outcomes in both still very much on a knife-edge.

In GP2, Racing Engineering's Rabio Leimer has a seven point lead over Russian Time's Sam Bird coming into this weekend's final round in Abu Dhabi, but with as many as 48 points available (for a sweep of pole, feature and sprint wins and fastest laps in both races) it's clear that that sort of margin could be lost by a single mishap as early as Friday morning.

"It's good to go to Abu Dhabi with a seven point lead, but we have to focus on the race weekend and not the championship," insisted Leimer, all too aware of how precarious a grid has has on the top spot. "We will concentrate on doing a good job, as we have done all year long."

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"In the end a championship is not won or lost during one weekend," commented Alfonso de Orl?ans-Borb?n, president of Racing Engineering. "It's the result of the work done throughout the entire season and I have to say that our boys have worked hard to achieve the results so far. For Fabio and the entire team it would simply be perfect to snatch the title and, in this fashion, finish off a season full of dedication and hard work."

Not helping Leimer or anyone else come to that has been the interminable six-week wait for the finale since the penultimate round in Singapore, but Leimer said that it's simply one of those things that has to be coped with.

"It was a quite long break, but nothing changed. My preparation is still the same as it was at the beginning of the season," he said. "I do not like the idea of changing something during a season when it has worked well so far.

"Pressure is not a problem because we have been working for this for several years. There is no reason to become nervous when you finally get the chance to achieve what you have worked for so hard for," Leimer added.

While the pressure might be on Leimer and his team, that seven point advantage they hold over Bird could still mean that it's possible they could clinch the 2013 championship as early as Saturday afternoon if Leimer wins the race and Bird suffers a nightmare. Not that Bird is the only challenger left in the running - Carlin's Felipe Nasr has an outside chance of catching the lead duo, and even Stefano Coletti (Rapax) and James Calado (ART) are not yet mathematically eliminated - although in reality it would take a turnaround of truly epic proportions for them to triumph.

This weekend all the drivers will have a selection of Pirelli's P Zero White medium and P Zero Red supersoft compounds - the very first time that this tyre nomination has been used in the 2013 GP2 season, and this could prove to be a pivotal factor in the title decider.

"With only seven points separating championship contenders Fabio Leimer and Sam Bird, there's going to be pressure on the teams to ensure both races are error-free," said Mario Isola, Pirelli's racing director. "Yas Marina is the ideal circuit to conclude the GP2 championship as it incorporates several of the best features of other tracks we have been to this year. The surface is fast and smooth while the track layout tests every aspect of a driver's skill and a tyre's capability.

"The drivers will have to ensure they get everything just right: including tyre strategy, which will be of the utmost importance," he explained. "With the medium and supersoft nomination for GP2, there is likely to be a performance gap of around one second or more between the two compounds, so the crews will need to think carefully about the factors that could come into play and how to plan the strategy over the race weekend as a whole."

There's no equivalent prime/option split to worry about in the GP3 Series - the only compounds available are the medium slick tyre for dry wether and the wet weather counterpart that surely won't be needed in the desert this weekend. It takes away one variable at least from the title battle, which is just as close and tense here as it is in the GP2 championship with once again just seven points separating first and second place heading into the final weekend of the season.

It's possible that GP3 might even steal some or even most of the limelight from its big brother series this weekend, given that one of the contenders involved is MW Arden's Daniil Kyvat - the 19-year-old from Russia just handed the opportunity of a lifetime with Scuderia Toro Rosso in the 2014 F1 championship. Life would be just about perfect for the youngster if he could sign off from GP3 clutching the champion's trophy, but to do that he'll need to close the gap on ART's Facu Regalia in this weekend's two races.

Other than Alice Powell taking the place of the unavailable Meville McKee at Bamboo Engineering, there's only one other driver change expected this weekend with Trident's David Fumanelli announcing that he was being forced to sit out the last round of GP3.

"It's official now I'll not race in Abu Dhabi this [weekend] due to budget issues. It's really though to accept, but that's life," he tweeted on Wednesday. "I'll keep working hard to find solutions for my future! Good luck to all the boys out there!"

In his place will be 24-year-old Irishman Robert Cregan, returning to GP3 for the first time in over a year. "I am very excited to be racing with Trident this weekend, it all came together quite late but I think it is possible to get a good result," he said. "I have not raced since the last race in Monza in 2012 so I cannot wait to jump in the car. I have been following the series this year and with the new car and a very competitive field it will be a big challenge but one I am really looking forward to."

All of this weekend's action will be carried live in the UK on Sky Sports F1, starting with practice on Friday morning at 10.15am local time (6.15am GMT) for GP2 and 11.15am (7.15am GMT) for GP3.

Qualifying for GP2 takes place late on Friday at 6.55pm (2.55pm GMT) with the 28-lap feature race set for 12.10pm (8.10am GMT) on Saturday and the 20-lap sprint race taking place at 1.15pm (9.15am GMT) on Sunday.

For GP3, qualifying will get underway on Saturday at 10am (6am GMT) with the first of the two 14-lap races taking place at 6.35pm (2.35pm GMT) and race 2 set for Sunday at noon (8am GMT).