World tennis number two Roger Federer's reached the semi-finals of the Stockholm Open, after surviving a scare to beat fellow Swiss and Olympic gold medal partner Stanislas Wawrinka.
The 2-6 6-3 6-2 win to Federer means he takes on fourth seed Ivan Ljubicic next, after the Croat defeated countryman Ivan Dodig 4-6 6-2 6-4.
Earlier, second-seeded Swede Robin Soderling was beaten 7-6 6-1 by Germany's Florian Mayer in a big-serving battle.
Mayer next faces Jarkko Nieminen after the Finn put out American James Blake 6-0 6-2.
