It remains unclear whether late second language learners (L2ers) can acquire sufficient knowledge about unique-to-L2 constructions through implicit learning to build anticipations during real-time processing. To tackle this question, we conducted a visual world paradigm experiment to investigate high-proficiency late first-language Dutch second-language Mandarin Chinese learners' online processing of syntactic cues to count vs. mass interpretations in Chinese which are unique-to-L2 and never explicitly taught. The results showed that late Dutch-Mandarin learners were sensitive to a mass-biased syntactic cue in real-time processing, and exhibited some native-like anticipatory behaviour. These findings indicate that late L2ers can acquire unique-to-L2 constructions through implicit learning, and can automatically use this knowledge to make predictions.