Esteban Gutierrez will partner Adrian Sutil at Sauber in 2014, with Russian youngster Sergey Sirotkin assuming the role of test driver.

The announcements came in a series of press releases between 01:34 and 02:06 GMT, but a more friendly 19:34 and 20:06 Mexico City time, which is appropriate as Telmex is to continue its partnership with the Swiss team.

"We at Telmex and Telcel are very proud to continue being part of the Sauber F1 Team to keep consolidating our successful history in motorsport, particularly in Formula One and our driver development programme for Mexican and Latin drivers such as Esteban Gutierrez, a great young talent, friend and human being," said Carlos Slim Domit, Telmex' Chairman.

"We are proud that three years ago Telmex chose the Sauber F1 Team to enter Formula One with, and that our partnership has been an instant success," responded Monisha Kaltenborn. "We are very pleased to be able to continue the good cooperation, and think this is also a very good fit looking at a possible Grand Prix in Mexico. Telmex has been involved on different levels of motorsport for a number of years in various categories. We are pleased to be able to contribute to its vision on the top level of motorsports, and we are looking forward to further develop and strengthen our partnership with the corporation."

"I am happy to be able to continue as a driver for the Sauber F1 Team," said Gutierrez who first tested with the team at Jerez in late 2009 and finished his debut F1 season 16th and best rookie.

"It was a steep learning curve last season, but by working closely with the team I was able to improve continuously. It will be my fourth year with the team, the second as a racing driver, and I feel comfortable in taking the next step. The technical challenges in 2014 will be massive. Therefore it will be even more important to know well the people you are working with. I will do my very best to improve even more and support the team the best way I can."

"We are pleased Esteban will drive for us in 2014, because we believe he is a talented young racing driver," said Kaltenborn. "Last season he experienced first-hand how hard it can be for a rookie to step into Formula One. Nevertheless, throughout the season he improved significantly in qualifying as well as in the races and finished the year as the best rookie in the drivers' championship. Often the results didn't fully reflect his performances. I am confident Esteban will be able to use his experiences to gain results, and this will be helped by the fact he is very well acquainted with every member of the race team."

After much speculation, Sirotkin finally joined the team in August 2013 and has spent several days at the factory in Hinwil working with the engineers. In late September he drove a demo-run at the new track in Sochi, while in October he tested a 2009 Ferrari at Fiorano. Sauber's aim is to prepare him for his debut in Formula One.

"It's a big chance for me to become the test driver for the Sauber F1 Team," said the Russian. "I will work hard to improve myself and to extract the maximum out of this opportunity. Formula One is very complex, so it is important to get an opportunity like this. My main focus next year, however, will be the World Series by Renault, which is very competitive. This will give me the chance to prepare even better in order to be ready for the next big step."

"We have been working with Sergey since August," said Kaltenborn, "and he has been able to gain more and more insight into Formula One. Now he is taking the next step towards the top level of motorsport in his new role as a test driver. Our experience of him is as a very focused, calm and talented driver. Now we will continue to support him, including obtaining his super license. Our goal remains to prepare him for a debut in Formula One."