Mercedes Formula E chief Ian James believes the team has found a “sound basis” from which to build on after concluding the three-day pre-season test at Valencia on Friday.

Mercedes will make its debut in Formula E next month at the 2019-20 season opener in Ad Diriyah, Saudi Arabia, having evolved from the HWA Racelab team that raced through the previous campaign.

Stoffel Vandoorne and Nyck de Vries completed a combined total of 259 laps through the three-day test, but lost chunks of running due to issues that James conceded came as a surprise.

"The first two days of testing this week were tough for us,” James said. “There were some challenges to overcome that we had not anticipated. It was unexpected, to be honest, but we found the right solutions.

“It just goes to show how important these test outings are in the run-up to the season. We were consistent when conducting our own private tests and found some stability. We must now ensure that we can achieve that again during the first race weekend.

“After a difficult start to the week, we've finished Friday's test on a positive note. I think we've created a sound basis on which to build, so that we can continue to develop during the season."

Vandoorne and de Vries ended the final day of testing P17 and P21 respectively in the classification, but James said it was hard to predict where Mercedes would stack up in the pecking order heading to Ad Diriyah.

“What we're trying to do at the moment is improve consistency," said James. "But of course, we want to be competitive when we get started. Valencia is a permanent race track that is very different to the street circuits we would normally compete on during the season.

“In addition, each team follows a different programme during testing, so it's not easy to draw comparisons. Therefore, we don't yet have the final picture in terms of how competitive we are compared to other outfits.”

The 2019-20 Formula E season gets underway with the Ad Diriyah E-Prix on November 22-23.