Al – 20 wt% Ce alloy particles with varying eutectic morphologies and sizes were fabricated using high cooling rate impulse atomization. Nanoindentation and in situ compression in a scanning electron microscope were used to evaluate the hardness, flow strength and plastic deformability of individual phases (Al and Al11Ce3) and various Al11Ce3/α-Al eutectic morphologies. The mechanisms that determine compressive strengths, plastic deformability and fracture of the intermetallic phase are interpreted in terms of the eutectic morphology and spacing. Fine, degenerate eutectic structure facilitated significant strain hardening and delayed onset of cracking, making it highly resilient under compression, while the fine and regular eutectic structure showed relatively lower strengthening and early crack nucleation compared to coarser lamellar eutectic structure. This study reveals the significant effects of microstructure morphology as well as size, specifically focusing on the degenerate eutectic microstructures at submicron scale, in controlling the flow strength and plastic deformability of fine-scale metallic eutectic microstructures containing hard, intermetallic phases.