Closing in on Formula One leader Sebastian Vettel, Ferrari driver Fernando Alonso suggested Red Bull's complaints about Pirelli's fast-degrading tires are due to frustration at no longer dominating races.

Red Bull star Vettel finished fourth when Alonso won the Spanish Grand Prix two weeks ago to reduce the gap to the German to 17 points.

But the race was overshadowed by Pirelli's tires shredding, forcing most teams to take four pit stops. Vettel was critical afterward, saying "we are not going to the pace of the car — we're going to the pace of the tire."

Alonso said Wednesday at the Monaco GP that "sometimes when you win too easy for some years it is difficult to lose some races afterwards."