For 2005, he stayed with Renault.
Alonso visited the team's factory in Enstone during pre-season for a seat fitting to feel comfortable in the R25.
He felt the more powerful and driveable car was more constant over a long period of time and that it had improved braking and stability.
The media considered Renault the pre-season favourites to win the championship and predicted a closely fought duel between Alonso and his teammate Giancarlo Fisichella.
Alonso said he entered the year in a positive mood and push hard and enjoy racing.

He and McLaren's Kimi Räikkönen team vied for the championship that year due to regulation changes mandating teams not to change tyres during a race and engines had to last for two races before they could be changed.
Alonso drove a more reliable R25 than Räikkönen's car albeit lacking in outright pace.
He was occasionally conservative to accumulate points rather than duel for wins.
Alonso took seven victories, six pole positions and the reliability of his car and consistent results allowed him to claim his first drivers' title two rounds early at the Brazilian Grand Prix.
Alonso became the youngest Formula One world champion at the age of 24 years and 58 days, eclipsing Emerson Fittipaldi's record the latter had held since 1972.
He concluded the season with 133 points from finishing all but two out of 19 races and had 14 top-three finishes.

Negotiations to extend Alonso's contract to the end of 2006 began with Renault in April 2005.
Jean Todt was interested in bringing Alonso to Ferrari, something the latter did not want because of the presence of the seven-time world champion Michael Schumacher.
Alonso signed a two-year contract with Renault that same month.
A majority of bookmakers considered him the favourite to retain the drivers' championship.
Alonso believed Schumacher and Honda driver Jenson Button would challenge him.
He said he was better relaxed.
less stressed than the year before and was more motivated and interested because Renault were defending the championship:
That season, Schumacher was Alonso's primary rival in the championship.
Alonso won six of the season's first nine races and finished in the top two positions to score a possible 84 out of 90 points.
A Fédération Internationale de l'Automobile (FIA; Formula One's governing body)-imposed ban on Renault's tuned mass damper device reduced Alonso's performance and an increase of development into Schumacher's Ferrari allowed him to go from being 25 points behind Alonso to level the total number of points the latter had accumulated before the penultimate round, the Japanese Grand Prix.
Alonso won after Schumacher retired with an engine failure while leading.
Alonso required one championship point at the season-ending Brazilian Grand Prix to claim his second drivers' title.
By finishing second, Alonso became Formula One's youngest two-time world champion aged 25 years and 85 days.
For 2005, he stayed with Renault. Alonso visited the team's factory in Enstone during pre-season for a seat fitting to feel comfortable in the R25. He felt the more powerful and driveable car was more constant over a long period of time and that it had improved braking and stability. The media considered Renault the pre-season favourites to win the championship and predicted a closely fought duel between Alonso and his teammate Giancarlo Fisichella. Alonso said he entered the year in a positive mood and push hard and enjoy racing.
He and McLaren's Kimi Räikkönen team vied for the championship that year due to regulation changes mandating teams not to change tyres during a race and engines had to last for two races before they could be changed. Alonso drove a more reliable R25 than Räikkönen's car albeit lacking in outright pace. He was occasionally conservative to accumulate points rather than duel for wins. Alonso took seven victories, six pole positions and the reliability of his car and consistent results allowed him to claim his first drivers' title two rounds early at the Brazilian Grand Prix. Alonso became the youngest Formula One world champion at the age of 24 years and 58 days, eclipsing Emerson Fittipaldi's record the latter had held since 1972. He concluded the season with 133 points from finishing all but two out of 19 races and had 14 top-three finishes.
Negotiations to extend Alonso's contract to the end of 2006 began with Renault in April 2005. Jean Todt was interested in bringing Alonso to Ferrari, something the latter did not want because of the presence of the seven-time world champion Michael Schumacher. Alonso signed a two-year contract with Renault that same month. A majority of bookmakers considered him the favourite to retain the drivers' championship. Alonso believed Schumacher and Honda driver Jenson Button would challenge him. He said he was better relaxed. less stressed than the year before and was more motivated and interested because Renault were defending the championship:
That season, Schumacher was Alonso's primary rival in the championship. Alonso won six of the season's first nine races and finished in the top two positions to score a possible 84 out of 90 points. A Fédération Internationale de l'Automobile (FIA; Formula One's governing body)-imposed ban on Renault's tuned mass damper device reduced Alonso's performance and an increase of development into Schumacher's Ferrari allowed him to go from being 25 points behind Alonso to level the total number of points the latter had accumulated before the penultimate round, the Japanese Grand Prix. Alonso won after Schumacher retired with an engine failure while leading. Alonso required one championship point at the season-ending Brazilian Grand Prix to claim his second drivers' title. By finishing second, Alonso became Formula One's youngest two-time world champion aged 25 years and 85 days.
Motor racing career of Fernando Alonso