SPA-FRANCORCHAMPS, Belgium - Lewis Hamilton will be out to show his victory in Hungary could be the launch pad for a title challenge as the Formula 1 season resumes with the 2013 Belgian GP on Sunday after a four-week holiday break.The summer holiday came at perhaps the wrong time for the momentum of the Briton who has given himself an outside chance in this his maiden year with Mercedes of winning a second Drivers' championship; the other was in 2008 title with McLaren.However Mercedes sports chief Toto Wolff said in an interview there was no point in thinking about what might have been as the teams move to Spa-Francorchamps and the longest circuit on the F1 calendar. "The break is the same for all the teams and although we won (the previous race) in Hungary it is a good thing and also important to let all the workers enjoy this rest," he said.'FANTASTIC CIRCUIT'Red Bull's Sebastian Vettel holds a 38-point lead at the top of the standings with 172 points after 10 of 19 races. Lotus driver Kimi Raikkonen has 134, Ferrari's Fernando Alonso 133, Hamilton 124."It feels like I've been out of the car for a very long time since the win in Hungary and I can't wait to get going again," Hamilton said. "Spa is a fantastic circuit and it's so much fun to drive. We're all looking forward to the second half of the season and the opportunity to bring home some more good results."Can Hamilton really be in the mix for the Drivers' title - a scenario unlikely when he left McLaren in 2012 to join Nico Rosberg at the team? "That's a difficult question," Wolff said. "If you'd asked me that six months ago I would have said 'unrealistic'. To get out of this way of thinking is not so easy. I would say at the present time: the team has developed really satisfactorily in the first half of the season."We've got to grips with some problems; we have a very good team atmosphere. We now want to build on this and to deliver the best-possible performance race for race. We have just reached the halfway mark and to start speaking about the title - if you take into account where we have come from - would be presumptious."RAIKKONEN VETTEL'S NEMESISTeam principal Ross Brawn said Rosberg and Hamilton were "rarin' to get back in the car again". "As usual, we will have a unique aerodynamic package adapted to the Spa layout. We finished the first half of the season on a high and will be aiming for an equally strong second half."Vettel's chief rivals still appear to be Raikkonen, who's looking for his fifth victory at the demanding seven-km circuit in what is one of the classic grands prix of the season, and Alonso, who has yet to win in Belgium. Alonso said: "Spa is a very special circuit that always gets your adrenalin pumping, what with the way the track rises and falls and the very quick corners, which all go to make it a really fantastic experience."The race at Spa also highlights how McLaren has struggled in 2013 since Jenson Button gave the team victory in 2012 from pole. Button looks back at that race as "pretty much the perfect weekend" but knows there will be no repeat on what he, like many other drivers, regards as one of his favourite circuits.The Briton, on 39 points, is only ninth in the standings; team mate Sergio Perez has 18.Button said: "We don't go to Spa with a package to win but I'll still be making the most of every single lap around this place - it'll still feel incredible," Button said.