Following top seed David Ferrer's withdrawal on Monday, Russian fifth seed Tursunov decided not to compete against Dutch home hope De Bakker due to a foot injury.
De Bakker will now face Joao Sousa in the quarter-finals in 's-Hertogenbosch after the Portuguese beat Croatia's Mate Pavic 6-2 6-4.
Second seed Fernando Verdasco, favourite to win the tournament in Ferrer's absence, also progressed to the last-eight of the grass-court tournament in relatively easy fashion, overcoming Jesse Huta Galung of the Netherlands 7-5 6-3.
The powerful Spaniard produced a composed display to claim victory, winning 85 per cent of points on his first serve as he dispatched of the wildcard.
Verdasco's compatriot Roberto Bautista-Agut endured a more challenging second-round encounter, overturning deficits in each set to dispose of Australian Matthew Ebden 7-5 7-6 (7-1).
Ebden spurned four set points in the opener, which he surrendered to Bautista-Agut after racing into a 4-0 lead, and the second set followed a similar pattern as the third seed came back from 3-0 down to win in a tie-break.
Bautista-Agut's triumph sets up an encounter with defending champion Nicolas Mahut of France, who totalled 14 aces on his way to a 6-2 7-6 (7-4) success over American Steve Johnson.
Canadian Vasek Pospisil was the most impressive victor of the day as the sixth seed needed just one hour and five minutes to hammer Germany's Jan-Lennard Struff 6-4 6-2.
Pospisil will now meet another German in Benjamin Becker - a 6-2 7-5 winner over Israel's Dudi Sela - in the quarter-finals.
Elsewhere in the draw, Austria's eighth seed Jurgen Melzer booked a clash with Verdasco by coming from behind to beat Lukas Lacko of Slovakia 5-7 6-3 6-3.