Andy Murray knows exactly how to "neutralise" ace master Ivo Karlovic's shotgun serve, according to Tim Henman.
Giant Croatian Karlovic stands between 2013 Wimbledon champion Murray and an eighth consecutive SW19 quarter-final appearance.
Murray meets 6ft 11in Karlovic second on Centre Court in today's hectic fourth-round schedule, with the winner facing either Vasek Pospisil or Viktor Troicki in the last eight.
Karlovic has served more aces than anyone in tennis history, blasting 136 alone in his three Wimbledon matches this year - but former world number four Henman hailed Murray's return of serve as "one of Andy's greatest attributes".
"Karlovic is one of the guys who will serve aces on any court with any ball, and especially grass, so that makes him a very dangerous opponent at Wimbledon," former British number one Henman said.
"Serving well on a grass court is always a tricky combination.
"Along with John Isner and Kevin Anderson, he's got a great motion, he serves extremely well - and when you're at the top-end of six feet then it certainly helps."
Zagreb-native Karlovic shrugged off viral meningitis two years ago, making a complete recovery to climb the world rankings back to number 25 at the age of 36. The oldest man in Wimbledon's second week since 1976 came to professional tennis late on, and has adopted a nothing-to-lose attitude since the health scare that threatened his career and more in 2013.
Murray has beaten Karlovic in all five of their meetings, so no matter what the bombardment, the Scot will be confident he can keep his tilt for a second Wimbledon title alive.
One five-time Wimbledon champion is guaranteed to reach the women's quarter-finals. Another is assured of elimination.
That's what will happen today when Serena Williams plays older sister Venus Williams for the sixth time at the grass-court Grand Slam in southwest London.
"They've been unbelievable for the sport. I've said that many times," said Roger Federer, a seven-time Wimbledon champion who will also be playing on Manic Monday. "Their head-to-heads, I don't know how much that has to do with it. I think it's more their individual play."
Against each other on the grass at Wimbledon, Serena leads 3-2, with all three of her wins coming in finals. Venus won one final, and also won a semi-final match against her younger sibling in 2000 - the first time they met on court at the tournament.