Many football fans will tell you there is no better competition than the F.A. Cup. The tournament, which is in its 138th edition, allows any team in the top 10 tiers of the English Football pyramid to enter, plus has extra qualifying rounds for teams not in those leagues to play their way into the draw. This season, 736 teams tried to make their way into the proper draw, and the competition has been whittled down to the final 32 teams. The fourth round (which starts Friday and goes through Monday) will kick off with the top match of the weekend, as Alexis Sanchez heads back to the Emirates Friday as part of the newly-prolific Manchester United attack. He will try to keep Ole Gunnar Solskjaer’s unbeaten start to his Manchester United career going, as the Red Devils take on Arsenal. There are three other all-Premier League ties. Manchester City will host Burnley, and Newcastle United will see Watford visit St. James’ Park, both at 10 a.m. Saturday. On Sunday, Crystal Palace will host short-handed Tottenham, which will come in off a Carabao Cup semifinal Thursday with Chelsea. The Spurs attack has been ravaged by injuries to Harry Kane and…