David Ferrer has made a career, not to mention a lot of money, out of his fighting qualities.
He's not blessed with a booming serve or big forehand but there are few who can slug it out quite like the diminutive Spaniard. The world No 3 needed to draw on his battling abilities again last night in his second-round match against American qualifier Donald Young, eventually prevailing 6-7 (5), 6-3, 6-1 in one hour 55 minutes.
It was a result the tournament needed - Ferrer is top seed and four-time champion - but he was pushed and the first set, in particular, was a battle.
Both players struggled to hold serve in the opening set and at one point there were six consecutive breaks of serve. Young played near the top of his game at times, illustrating why he rose to 38 in the world in 2012, and eventually claimed a set that lasted 59 minutes 7-5 in the tiebreaker.
From there, Ferrer started to take control. He lifted his game, finding the lines beautifully, and Young couldn't maintain his standard under sustained pressure.
Ferrer broke Young early in the deciding set and soon set up a quarter-final against compatriot Guillermo Garcia-Lopez, who emerged from a marathon three-setter with Colombian Santiago Gilermo.
Young's defeat was a rare lowpoint for American players who filled three spots in the quarter-finals.
World No 14 John Isner eventually overcame qualifier Lukas Lacko and a sore ankle to win 7-6 (1), 3-6, 6-2 and he was joined in the last eight by compatriots Jack Sock and Steve Johnson.
Sock beat second seed Tommy Haas 6-4, 6-4 - at world No 12, Haas is the highest ranked player Sock has beaten - and he will take on Spaniard Roberto Bautista Agut who ousted sixth seed Benoit Paire.
Sock used his serve and big forehand to good effect against an out-of-sorts Haas, who was playing his first match of the year. Haas received a first-round bye as one of the tournament's top four seeds.
"It's exciting but I have to keep my head looking forward and get ready for tomorrow," Sock said. "I came into the year with high expectations. I put in a lot of work in the off-season and feel good about my game. Hopefully I can keep it going."
Sock, who received a wildcard for the Heineken Open, spent considerable time in that off-season training with Johnson.
Johnson gained entry to the tournament only as a lucky loser, after earning a place in the main draw when Gael Monfils withdrew. He started the day by beating former world No 8 Marcos Baghdatis 7-5, 6-7 (3), 6-4 and followed it up with a 7-5, 6-4 defeat of fourth seed and world No 20 Kevin Anderson of South Africa.
"There are so many ups and downs [in tennis] but to beat those two guys on the same day is pretty special," Johnson said.
"Marcos is an incredible guy. I can remember watching him in the final of the Australian Open at 1am or 2am in the morning [US time]. I have watched him since I was 13 so it was an unbelievable morning for me and then to come out and beat Kevin ... it's been quite a day."
It's been an interesting period for Johnson. Last week the world No 160 was beaten by New Zealand's Rubin Statham at a Challenger event in Noumea and last year he made a "rookie mistake" when he failed to enter for the Australian Open qualifying tournament but earned a wildcard for the year's first grand slam instead by winning the US Tennis Association playoffs which guarantees a place in Melbourne for the winner.
Heineken Open - Day 4
Centre Court - 12pm
Roberto Bautista Agut (ESP) vs [WC] Jack Sock (USA)
Philipp Kohlschreiber (GER)  vs John Isner (USA) 
[LL] Steve JOHNSON (USA) vs Yen-Hsun LU (TPE
Not before 6.30pm
David Ferrer (ESP)  vs Santiago Giraldo (COL) or Guillermo Garcia-Lopez (ESP)
Eric Butorac (USA)/Raven Klaasen (RSA) vs Jamie Murray (GBR)/John Peers (AUS) 
Court 4 - 2pm
Santiago Gonzalez (MEX)/ Scott Lipsky (USA)  vs Daniele Bracciali (ITA) / Lukas Dlouhy (CZE)
Andre Begemann (GER)/ Martin Emmrich (GER) vs Julian Knowle (AUT)/Marcelo Melo (BRA) 
Alexander Peya (AUT)/Bruno Soares (BRA)  or Juan Sebastian Cabal (COL)/Robert Farah (COL) vs Frederik Nielsen (DEN)/Igor Sijsling (NED) or [Alt] Roberto Bautista Agut (ESP)/Daniel Gimeno-Traver (ESP)