Systematic rhymes with:
asymptomatic, automatic, semiautomatic, symptomatic, aromatic, asymptomatic, automatic, axiomatic, cinematic, diagrammatic, diplomatic, dramatic, emblematic, epigrammatic, idiomatic, mathematic, melodramatic, problematic, programmatic, psychosomatic, semiautomatic, symptomatic, telematic, undiplomatic
Systematic sounds like:
sediments, sixteenths, standex, standish, standouts, stands, statement's, statements, steinmetz, stendig, stentz, stints, student's, students, students', stunts, stuntz, systematics