Ferrari appeared to find its way with the new F138 car following a difficult start at Jerez, Spain. Mercedes' Nico Rosberg said he noticed Felipe Massa struggling with the new car at the beginning of the first test.Rosberg said: "On the first two days, the Ferrari did not look good."Massa ultimately went on to set the fastest lap time of the entire four-day test.'DROVE AS ON RAILS'Rosberg commented: "Obviously, they found a solution to the problem," adding that the 2013 Ferrari ultimately seemed "quite good".Perhaps not as good as Red Bull or McLaren, he added: "They drove as though on rails."Ferrari's early struggles could be explained by a delay to the F138's development programme, caused by the push for the 2012 title.Technical director Pat Fry said: "If we talk about the aerodynamics of the F138, we started about three months later than we would have liked. We will do everything to make up for this delay."Fry referred to a stream of forthcoming "innovations" for the new red and black car. One of them may be a mysterious hole beneath the nose tip that emerged in the final moments of the Jerez test.