Born in Barcelona, Clos was a fairly successful karter at the ICA Junior level of karting, winning firstly the Catalan district of the Spanish ICA Junior Championship in 2001, beating a field including the brother of former Formula Three Euroseries rival Daniel Campos-Hull, Oliver.

Clos adapted to the cars very well, and ended up a solid 4th place in the championship behind Michael Herck, Marco Barba and Arturo Llobell, with one win and four podiums along the way.

Clos struggled in the pan-European championship, failing to record a finish inside the top ten placings all season.

He was slightly more successful in the Italian series despite missing three races due to Eurocup commitments, finishing sixteenth in the championship with 28 points beating teammate Oliver Campos-Hull in the process.

He had originally done the double at Misano, which would have taken his tally to four in succession, however he was disqualified due to his car's diffuser height not complying with Eurocup regulations.

He recorded four double victories at Spa, Hockenheim, Misano and Monza and finished second in the single-race meeting at Varano.

His best result was a fourth place during the reverse-grid round sixteen in Barcelona – the race now infamous with one of the biggest startline crashes in Euroseries history, in which nine cars were eliminated.

Clos made his debut in Formula Renault 3.5 Series at Le Mans for Epsilon Euskadi, replacing Adrián Vallés, who was busy driving the Liverpool F.C.

A ninth-place finish was his best result of the weekend, which also included an incident with teammate Chris van der Drift.

The team also competed in the GP2 Asia Series for the first time, in which Clos, partnered with Nathanaël Berthon, scored a race win at Imola to finish ninth in the championship.

Clos began the 2012 season without a drive, but was drafted into the Barwa Addax team after the first round of the championship, replacing Josef Král and alongside Johnny Cecotto.

[15] Clos also took part in the Abu Dhabi young drivers' test on 15 November 2011 at the Yas Marina Circuit.