Half of England and Belgium want their teams to lose
I think winning is the best option. England and Belgium are qualified and will face whatever comes out of Group H in the round of 16. No matter which team finishes first or second, England and Belgium are favorites to win their round of 16 games. Then, if you lost today, you will probably face Switzerland in the QF. If you won today, you're likely to face Brazil. What would you rather have: face Brazil as an unbeaten team or face Switzerland with a loss under your belt? If you win from Switzerland (or Sweden) you will go on to face either Spain or Croatia and I would NOT want to face Croatia, knowing I lost to Belgium/England. At this point, you have to take it from game to game, you can't afford to have your eyes on the finals. I'd say: whoever you root for tonight, better hope for a win.