Don't play minesweeper, but I've played Freecell a little bit.
Longest winning streak was about 15 or so as I recall, averageing wins at about 90%.
At this one local RV Park for snow birds they have this small computer lab of four computer that anyone in the RV park can use. They have internet access and a few games installed.
Anyways, while I was poking around on one I noticed the Freecell log indicated someone had a losing streak of something like 147 (!), and the longest winning streak was 7. Yikes!