Seventeen-time Grand Slam winner Roger Federer says he did not expect to reach the Australian Open semi-finals after a six-month injury lay-off.
The four-time champion in Melbourne is making his competitive return after last playing at Wimbledon in July.
Federer beat Mischa Zverev 6-1 7-5 6-2 to set up Thursday's last-four match against fellow Swiss Stan Wawrinka.
"Feeling as good as I am, playing as good as I am, that's a huge surprise to me," said the 35-year-old.
"If someone would have told me I'd play in the semis against Stan, never would I have called that one.