Ninth in Liège-Bastogne-Liège last year - his best Ardennes result to date - and 32nd last year at La Flèche Wallonne 2013, Costa refused to be drawn on which of the two hilly Classics left to race suited him better.
"We'll see when the racing starts," he told Cyclingnews, "[Race winner Philippe] Gilbert (BMC) was very fast and very strong in Amstel Gold, so was [Alejandro] Valverde [Movistar]."
Either way, he points out, his own form is more solid than it had appeared in his last race outing, the Vuelta al País Vasco, where he finished 51st, more than half an hour down on winner Alberto Contador (Tinkoff-Saxo).
"I've worked hard to be good in these Classics, in País Vasco I was not as good as I’d hoped, but at least on Sunday I was in relatively good shape."
At Amstel Gold, Costa crossed the line in 17th place, just 12 seconds down on Gilbert.
The reigning World Champion has yet to win a race in 2014, but he has come close on several occasions, with his best result to date a second place in Paris-Nice. The last rider to win a Flèche Wallonne with the rainbow jersey on his back was Cadel Evans — currently racing in the Giro di Trentino — back in 2010.
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