Firepower
Both planes are equipped with state-of-the-art missiles capable of shooting each other out of the sky. The Su-35's need to carry ordinance outside the fuselage is a slight disadvantage, but in general, the first plane to score a clean hit will win.
The Su-35 can carry 12 missiles, while the F-22 carries just eight, but as Justin Bronk from the Royal United Services Institute notes in an interview with Hushkit.net, the Su-35 usually fires salvos of six missiles with mixed seekers, meaning the 12 missiles only really provide two credible shots.
The F-22 could engage the Su-35 from farther away as it is harder to detect due to its stealth advantage, so it could potentially make more economical use of its missiles.