Quantitative flow ratio (QFR) based on three-dimensional quantitative coronary angiography (3D-QCA) is a novel method to assess physiological functionality after treatment with stents. The current study aimed to evaluate the difference in physiological functionality nine months after implantation of a bioresorbable polymer-based sirolimus-eluting stent with an electrografting base layer (BuMA Supreme: B-SES) versus a durable polymer-based zotarolimus-eluting stent (Resolute: R-ZES). The current post hoc analysis was performed in the PIONEER randomised trial (1:1 randomisation to B-SES 83 patients/95 lesions and R-ZES 87 patients/101 lesions). QFR was measured in stented vessels in both arms at preprocedural, post-procedural and nine-month angiography without pharmacologically induced hyperaemia (contrast QFR). At nine months, both the values of QFR distal to the stent (B-SES: 0.89±0.10 vs. R-ZES: 0.89±0.11, p=0.97) and the number of vessels with QFR ≤0.8 were not significantly different between the two groups (11.0% vs. 12.8%, p=0.72), while the in-stent binary restenosis rate was also comparable (3.7% vs. 3.5%, p=1.00). QFR gradient across the device (∆QFR) at nine months was also similar between the groups (B-SES: 0.03±0.04 vs. R-ZES: 0.03±0.07, p=0.95). Quantitative flow assessment nine months after stenting did not differ between B-SES and R-ZES, despite a significant difference in in-stent late lumen loss.