Former Trawlerboy Rickie Hayles denied Lowestoft a deserved share of the spoils with a match-winning goal 15 minutes from time.
Lowestoft were on the defensive for most of the game – not a surprise given their opponents have a nine-point lead at the top of the table.
With Travis Cole and Jake Reed both suspended, the last thing manager Dale Brooks needed was for both Adam Smith and Harry Barker to drop out through injury. Jacek Zielonka dropped into the left back role with Harvey Hodd and Nico Cotton coming into midfield and Shaun Bammant joining Matty Foy up front.
Although mainly on the back foot, it was Lowestoft who created the first real shot at goal when the ball was moved quickly from Zielonka to Sam Borrer to Hodd whose 25-yard effort was a foot too high.
Dulwich were using the flanks well, with the combination of Quade Taylor and Sanchez Ming looking particularly dangerous down the right and Nathan Ferguson dominating in midfield. However, despite seeing a lot of the ball, Dulwich were not able to create any real opportunities, with Ben Dudzinski claiming everything that came his way.
The Trawlerboys keeper was called into action to save a vicious low cross into the area after good work by Ming and then got down well again moments later to save at full-length from Muhammadu Faal.
Lowestoft still threatened on occasions, with Cotton coming more into the game after a slow start and crossing low into the area, although Foy's touch sent the ball wide of the upright.
The second half followed a similar pattern, with Lowestoft soaking up the pressure, but it needed an excellent save from Dudzinski to turn Faal's header over the bar.
But all Lowestoft's hard work was undone in the 75th minute when Dudzinski pushed Nathan Green's near-post shot wide, but from the resulting corner Ashley Carew's flag kick saw Hayles send an unstoppable header into the roof of the net.
Lowestoft refused to let their heads drop and came close to snatching an equaliser, with Foy slipping the ball to Hodd who cut inside his marker before placing his shot a bit too near to keeper Preston Edwards who was able to parry it away.
Dulwich Hamlet: Edwards, Taylor, Green, Onovwigun, Hayles, Weatherstone, Ming, Carew, Allassani, Ferguson (Beaney 90), Faal (Kargbo 90), Subs not used: Abrahams, Acheampong, Boakye-Yiadom.
Lowestoft: Dudzinski, Humphretys, Zielonka (Nyadzayo 82), Fisk, McAuley, Jarvis, Hodd, Borrer, Bammant, Foy (Greenleaf 86), Cotton. Subs not used: Wren, Putnins.
Referee: M Lowe
Attendance: 1,832
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