Toro Rosso driver Jean-Eric Vergne admitted that he had feared he might struggle in Monaco, so was relieved to outpace team-mate Daniel Ricciardo in Thursday practice.
Vergne made his Monte Carlo debut in the Formula Renault 3.5 support race last year, but struggled to 12th place.
The Frenchman confessed that had left him nervous about his first Formula 1 performance at the famous venue, so edging Ricciardo - twice a Monaco winner in FR3.5 - in both sessions as he took 14th in the morning and 17th in the afternoon, was a confidence boost.
"This was my first time here in a Formula 1 car and I really enjoyed myself," said Vergne.
"Because I did not go particularly well round Monaco in the World Series last year, I was a bit apprehensive about today, although still looking forward to a new experience and not knowing what to expect.
"I think my performance today compared quite well to my team-mate, as Daniel won the last two World Series races he drove at this circuit and he had also had some practice time in the F1 car last year.
"From that perspective, I am quite happy and I feel the lap time was not important, especially as I had a bit of traffic and I finished my fastest lap in the pitlane."
Vergne believes there is more time to come from his confidence and circuit knowledge than from car improvements.
"I am relatively pleased with the balance of the car which we can fine tune a bit further, but I still need a bit more time to adapt myself to this circuit, even if I liked driving it when it was wet," he said.