Arden driver Razia's 5.6-second winning margin did not reflect how close the action was in mainly dry conditions, although increasing amounts of drizzle made things tricky.
From fourth on the grid, he passed Valsecchi's DAMS car for third on the opening lap around the outside of Stowe. On lap two, he dived past Felipe Nasr (DAMS) for second at Brooklands and quickly homed in on poleman, and early leader, Giedo van der Garde (Caterham). Razia repeated his earlier brave pass around the outside of Stowe on the Dutchman but was not able to pull away.
That was because Nasr lunged past van der Garde at The Loop on lap three, and quickly re-attacked Razia. He jumped ahead of him with a bold outbraking move at Village on lap eight, only to run wide and allow Razia back past. That was one of three position changes in the top six, as Valsecchi passed van der Garde for third at Stowe, and Esteban Gutierrez overtook Max Chilton (Carlin) for sixth at Vale.
Razia got the hammer down at this point, and pulled away from Nasr. The Brazilian fell back into the clutches of his team-mate Valsecchi, and the Italian passed him on the exit of Stowe with six laps remaining.
Although he got to within under a second of Razia's lead on lap 18, Valsecchi gave up the chase and coasted home in second. He now trails Razia by six points in the championship, however, as a result.
Nasr held on to third, ahead of Gutierrez. The latter's removal of Johnny Cecotto from fourth, after running wide at Stowe and clattering into the Venezuelan as he rejoined, is likely to result in a stewards' enquiry. Cecotto (Addax) was fired into the tyre wall at Vale, and out of the race, with just a few yards remaining.
Jolyon Palmer finished fifth for iSport, ahead of Ocean's Nigel Melker.