ricciardo made his track debut at the wheel of a formula one car, when he tested for red bull racing at the young drivers test at circuito de jerez over three days, from 1–3 december 2009. on the final day of testing he clocked the fastest time of the test by over a second. this placed him as the only driver to go into the 1:17 bracket. red bull racing's team manager christian horner suggested that ricciardo may replace his 2010 world series teammate hartley as the team's test and reserve driver. as it turned out, ricciardo and hartley were to share test and reserve duties for both red bull, and sister team scuderia toro rosso until the latter was removed from the red bull junior team.