If 3. Na5 then 3...Bxc5 4. Nxc4 Bxa3 5. bxa3 dxc4 for an even exchange of material. It is a better move, but the white player didn't see this far enough in advance. He was planning 4. Nxe6 for control of the file for his rook, although I wasn't clear on how he was planning on getting his bishop out of the way.
Intricate Attack on the White Queen
If 3. Na5 then 3...Bxc5 4. Nxc4 Bxa3 5. bxa3 dxc4 for an even exchange of material. It is a better move, but the white player didn't see this far enough in advance. He was planning 4. Nxe6 for control of the file for his rook, although I wasn't clear on how he was planning on getting his bishop out of the way.
3. Na5 Bxc5
4. Nxc4 Bxa3
5. Nxa3 and white is up a piece.
There's a lot of forethought involved in this puzzle. Plan carefully!