Ferrari's Felipe Massa fears Lewis Hamilton could be more of a threat to his Formula One title ambitions than Fernando Alonso, the reigning double world champion.
Hamilton finished second to the Brazilian at Sunday's Spanish Grand Prix in Barcelona, and the Briton leads the standings on 30 points, two clear of his more illustrious McLaren team-mate Alonso.
Massa has won two races on the bounce following an indifferent start to the campaign and sits just one point behind Alonso.
In his first season in Formula One, Hamilton has now beaten Alonso in the past two races and has finished on the podium in each of this season's four Grand Prix.
Massa said the 22-year-old has caught the attention of Ferrari. He said: "It is Hamilton who leads right now and I have spoken quite a bit to him He is definitely strong and is not bothered by pressure.
"At the moment, you cannot say that Fernando or him are the better driver, but if the situation continues like this, then maybe Lewis can even be more dangerous than Fernando, given his championship position and how he goes in the car.
"At the moment he seems more comfortable in the car than Fernando. We need to keep an eye on that, because he can be a dangerous threat."
Massa admitted his frustration at lying third in the drivers' standings despite turning in immaculate performances in the past two rounds. He said: "What is unusual is that after three poles and two wins in a row, I am still only third in the championship. It shows we are moving in the right direction and that we have the momentum, but it also shows we need to keep working hard."