Coming into the last session tied at four apiece Trump continued where he had left off as breaks of 54 and 75 saw him open a two-frame lead.
Robertson dug deep and a break of 66 cut the deficit before another half-century saw Trump once again go clear and eventually within one of victory.
German Masters moved from Berlin due to Covid-19 restrictions
An epic safety battle in the 14th frame eventually went Robertson's way as he cut the gap once more.
However he couldn't prevent the inevitable as Trump got in amongst the balls and knocked in his first century of the match to seal victory.
'He's thriving!' - Trump seals victory with a ton
The result means that Robertson continued to lead the way in the BetVictor European Series, with the next event set to be the Shoot-Out.
Robertson, who is now under threat from his opponent for the overall title joked that Trump deserved a break and should skip the Shoot-Out.
Robertson jokes with Trump - Judd might want to reward himself with some time off!
Trump said he would "love" to play and take the money off Robertson and joked that maybe they "should both skip the Shoot-Out and have a face-off in Gibraltar."
Trump was quick to pay tribute to his brother Jack who has joined him on tour recently which has coincided with Trump's successful period.
"It speaks for itself," Trump said. "Since he started coming around with me around 14, 15 months ago I've won five or six ranking events he's turned my career around he's managed to get me back on track, practicing harder than ever,
'I owe all my success to him!' - Trump hails brother for impact on career
"So I owe all my success to him."
FIRST SESSION REPORT
Judd Trump recovered from 4-2 down against Neil Robertson to end the first session of the German Masters at 4-4.
It was two frames all after the first four, with Robertson scoring the only century (120) in the opening exchanges.
However the Australian took a 3-2 lead when he edge the fifth 72-71, before winning an easy frame in the sixth.
The European Championship winner had carried his excellent form over to Germany, before Trump attempted to mount a comeback when he went 74-0 before missing a red - Robertson could not capitalise and the score went to 4-3.
An extended eighth frame highlighted the competitiveness of the match as both players fought doggedly. It was Trump who clawed one back though to leave the game in the balance.
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