Tim Henman has called on Andy Murray to take the game to Roger Federer in their semi-final match at Wimbledon.
The Swiss holds a 12-11 advantage in their 23 meetings, and has also won the last three matches between the duo, although Murray won their last clash on Centre Court in the 2012 Olympics.
Federer has been in imperious form at the competition this year after only dropping a set on his way to the last four, which Henman feels forces the Scot to take the initiative to knock the 33-year-old out of his rhythm.
He told BBC Sport: "Andy Murray has to be aggressive. Roger Federer doesn't beat himself, he is so offensive, Andy needs to be proactive enough to get Federer on the back foot.
"A lot will be dictated by the serving. The person who has a good serving day will create the opportunities."
Federer and Murray play on Centre Court later today.