The Russian-owned team had kept the Ferrari-engined car back in their central England factory to fix problems that emerged shortly before it was due to be dispatched to southern Spain last weekend.
It finally arrived on Wednesday, in a trailer towed by a van, after a journey across the English Channel and down through France that started on Tuesday morning.
"The van actually broke down just south of Seville just to add to the drama," a relieved team principal John Booth told Reuters.
Marussia are the last of the 11 teams to reveal their car, although Lotus - absent from the Jerez test - have only released a computer-generated image, and Booth assured fans they would like what they saw.
The Formula One cars seen so far have been a mixed bag, with some sporting 'ugly' noses to meet new regulations and others like the Red Bull presenting a far more elegant front end.
"You will be amazed how pretty it is," Booth said of his car, which he hoped would be able to get out on track on Thursday morning.
He recognised his mechanics had a long night ahead.
"The systems are so complicated, I think it took everybody two days from finishing the car to firing it up," he explained.
Despite the hurdles, with many more sure to come on the track, he said it was essential to be at the test.
"There is so much new on the car that we don't even start to understand yet," he said.