"We know that our championship [hopes stay] alive maybe thanks to the first laps," BBC Sport quotes Alonso as saying.
"We are always qualifying around seventh or eighth and we finish the first lap in first three or four positions, and after that the race becomes easier. Today we knew there was a good chance [to] try to overtake people in the first corner.
"If we are in the leading group we can always keep the pace. Today was not possible to keep the pace with these two guys. This podium is like a victory for us."
The final race of the season is in Brazil next weekend.