Roger Federer kept up his good form on clay with a straight-sets win over Fernando Verdasco at the Hamburg Masters.

The world number one, who has won in Estoril and finished runner-up in Monte Carlo in the last month, beat the Spaniard 6-3 6-3.

Federer will face Nicolas Kiefer or Andres Seppi in the semi-finals.

Third seed Novak Djokovic saw off Albert Montanes 6-2 6-3 and will take on Rafael Nadal or Carlos Moya next.

Federer is a four-time champion in Hamburg and got his only win to date over Nadal on clay in last year's final.