After dropping points in September, the Blues have now rallied to move top of the Premier League under Antonio Conte.
Conte's men were held to a 2-2 draw by Swansea and beaten by rivals Liverpool and Arsenal two months ago but they have now won seven league games in a row to move one point above Liverpool.
They were too strong for Tottenham on Saturday in a 2-1 win with Pedro and Victor Moses grabbing the goals at Stamford Bridge.
Conte has refused to get carried away and Alonso agrees, but the Spaniard is also confident nobody will be able to match them if they can continue to produce the same standard of performances.
"We've got to go game by game and we will see at the end of the season," he told Chelsea TV.
"But if we're still playing this way, with this passion, with this energy, it's going to be tough to beat us."