[3] Delétraz began his single-seater career in September 2012, racing in the Grand Final of the Formula BMW Talent Cup season, held at Motorsport Arena Oschersleben in Germany.

[8] After winning the opening race of the season at Monza,[9] he took a further four podium positions to finish runner-up in the championship, sixteen points behind Fortec Motorsports Ben Barnicoat.

[10] During the year, Delétraz also made his debut in the Eurocup Formula Renault 2.0 championship, taking part in the rounds at Spa-Francorchamps, Nürburgring and Paul Ricard as a guest driver.

[14] Delétraz made his debut in the Formula Renault 3.5 Series at the fifth round of the 2015 season at the Red Bull Ring, driving for the returning Comtec Racing team.

[17] After a poor first half of the season, scoring only 1 point, he switched to Rapax, replacing Nyck de Vries who in turn took his place at Racing Engineering.

Delétraz switched teams for the 2018 season, moving to Charouz Racing System to partner former Ferrari Driver Academy member Antonio Fuoco.

Delétraz competed in the 2020 24 Hours of Le Mans Virtual and won it with Rebellion Williams eSports, driving the Oreca 07 in the LMP category alongside Raffaele Marciello, Nikodem Wisniewski and Jakub Brzezinski.

In 2021, it was announced that Delétraz would be competing with Team WRT in the European Le Mans Series in the LMP2 category alongside Robert Kubica and Yifei Ye.

After leading the race with one lap to go, the car, with Yifei Ye behind the wheel, stopped down the hill past the Dunlop Bridge because of a broken throttle sensor creating an electrical short circuit that temporarily turned the engine's electronic control unit off.

[35][36] During the ELMS season-opener at Barcelona, Delétraz managed to overcome a late pit stop for a change of his car's tail section to pass Neel Jani for the lead with 15 minutes to go, thus beginning RTT's season with an overall victory.

[37] Another class victory followed at Paul Ricard, though Delétraz would drop from the overall lead to third within the final few laps as a de-laminating tyre shredded parts of the car's bodywork.

[38][39] Bad luck hit the #34 crew at Aragón, where a prospective second place was scuppered during the final pit stop, as the car could not be fired up for eleven minutes, thus dropping them to ninth in class.

[43] Despite a strong race at the 24 Hours of Le Mans, the team were unable to beat the #34 of Inter Europol Competition; Delétraz losing out in the final stint to Fabio Scherer, who controlled the gap until the checkered flag.

[46] Thereafter, a controlled drive to victory in Fuji and a dominant display by WRT at Bahrain, one where the #41 took the lead late thanks to pit stop troubles for the #31 sister car, ended up guaranteeing Delétraz, Kubica, and Andrade the final ever LMP2 title in the WEC era.

[57] Parallel to his commitments overseas, the Swiss driver partnered with long-time teammate Kubica and prototype rookie Jonny Edgar at AO Racing by TF in the ELMS.

[58] Delétraz and AO by TF also took part in the 24 Hours of Le Mans as a Pro-Am entry with Alex Quinn and team owner P. J. Hyett, where the Swiss would go on to take pole position.