It looked as though we would leave Switzerland frustrated after a contentious late penalty brought the hosts level following Victor Moses's first-half opener, but David Luiz ensured we would take an advantage back to London, and a valuable second away goal, with the last kick of the game, a low free-kick that evaded Basel goalkeeper Yann Sommer.
'It's important to score two goals here. They are a very good team, and it was difficult to win here,' the Brazilian said afterwards. 'It was amazing to score the second goal but we have the second leg to come and one more difficult game.'
Mata, who replaced Eden Hazard in the second half, felt we could have had a greater lead before Basel's equaliser.
'To be honest I think we had more chances to score more goals,' he said. 'Their goalkeeper was great but at the end the result is very good for us and we're very happy.
'Now we arrived at the most important part of the season and it's important we stay together.'
There are of course still 90 minutes to go in the tie, but we are strong favourites to meet either Fenerbahçe or Benfica in Amsterdam next month.
'I want to go to the final, but it is not finished. This title is very important for us, and for me I want another title,' David Luiz said., with Mata adding: 'For the club it's very important to play in the Champions League next season, but now we have the chance to win another trophy so we will try our best until the end.'
There is an important Barclays Premier League game at home to Swansea City to switch attention to now, but the signs are good for next Thursday's return leg at the Bridge. Basel know they have work to do.