Alonso fastest in Barcelona
Fernando Alonso underlined Ferrari's promising pre-season form as he concluded his three-day stint at Barcelona with his best time of the week.
Alonso opted to skip the first test in Jerez a fortnight ago to rest and build up his fitness, the Spaniard finally sitting in the cockpit of the new F138 on Tuesday.
Allowed three successive days behind the wheel, Alonso conjured a lap of one minute 21.875secs around the Circuit de Catalunya to top the timesheet.
The double world champion's time, set on the soft compound of Pirelli tyres, was just 0.067s slower than that of Sergio Perez's quickest so far this week in his McLaren on Wednesday.
Nico Hulkenberg finally showed what the Sauber is capable of as the German finished second fastest, 0.285s adrift of Alonso, again on the soft tyre.
It was the same story for Romain Grosjean as he finished a third of a second down on the Spaniard in a Lotus in which team-mate which Kimi Raikkonen could only manage 87 laps over his two days due to a data issue on Tuesday and gearbox change yesterday.
Grosjean, however, completed a full race simulation of 66 laps in the afternoon which required four pit stops, for a total of 119 laps for the day overall.
Behind the leading trio were Mercedes' Nico Rosberg, who was fastest on Tuesday, and whose best time today of 1:22.611 was again on medium -compound tyres, just 0.005s quicker than two days ago.
The Williams' pairing of Pastor Maldonado and rookie Valtteri Bottas split the day's programme between them, with the Venezuelan finishing 0.151s quicker than the Finn.
Jenson Button enjoyed a steady day in his McLaren to wind up seventh and within a second of Alonso.
Down in eighth, and in an F1 car for the first time since the 2011 Brazilian Grand Prix was Adrian Sutil for Force India.
Vying for the second race seat at the team alongside current reserve Jules Bianchi, who takes up the reins on Friday - although rain is forecast for the entire day - the German posted a time of 1:22.877s.
Jean-Eric Vergne was within 1.5s of Alonso, whilst again considerably off the pace were Marussia and Caterham, with the former again having the upper hand on its backmarker rival.
Marussia's Max Chilton, however, was 3.815s adrift of Alonso, with fellow rookie Giedo van der Garde in the Caterham a further half a second down.