Top Eleven Tactics for the 4-2-3-1 formation

Summary

The 4-2-3-1 formation has become almost the standard in modern Top Eleven because of its flexibility.

Supportive team mentality

Defensive, Normal, Attacking, Hard Attacking

Unsupportive team mentality

Hard Defending

Advantages of the 4-2-3-1 formation in Top Eleven 

• Simply it creates more chances.
• With three attacking midfielders (AMR, AMC, AML) and a striker (ST) you can beat even a strong defense.
• If your opponent is using the Man-To-Man marking style in defense, your team playing the 4-2-3-1 will almost always have the numerical advantage in attack. 
• Your players cover the entire pitch and your strikers can attack from all angels.
• Your attacking center midfielder (AMC) can give a surprise anytime with his passing and long rang shots.
• This is the one of few formations in the game that can be used for all available focus passing styles "Mixed, Down Both Flanks, Right Flank, Left Flank, and Through The Middle. You can change your tactics between the match without changing formation.
• This formation is capable of all three available passing styles, Short, Mixed, and Long.
• The offside trap works really well with this formation.

Disadvantages of the 4-2-3-1 formation in Top Eleven

• In defense, most of the time it's one-on-one situation.
• The Man-To-Man marking style isn't sufficient against strong opponents.
• You need both of your center defenders (DC) very fit and strong. (at least 6 stars recommended overall, and at least 120% fitness and strength attributes)
• Pressing low isn't a good option.

Recommended special abilities

• Your striker (ST) should have the special ability of One-on-one scorer. It can be very helpful to score during counterattacks.
• Your attacking center-midfielder (AMC) should have a special ability of Shadow-Striker.
• For more creativity in the midfield, one of your central midfielders should have a special ability of Playmaker.
• Both of your center-backs should have the special abilities of Defensive Wall and Aerial Defender.

Recommended extra roles

• Both of your center midfielders (MC) should have an extra role of defensive midfielder (DMC). It helps to stabilize the defense.
• Your right, left and center attacking midfielders (AMR, AML, AMC) should have an extra role of Strike (ST). The strength attribute helps to play the ball against the defenders of the opposing team in one-on-one situation.

Attacking and Hard Attacking tactics for the 4-2-3-1 formation

Team mentality, Attacking or Hard Attacking, Focus passing, Mixed, Passing style, Mixed, Force counter-attacks, Off
Pressing style, High, Tackling style, Hard, Marking style, Zonal, Play offside trap, On

Normal tactics for the 4-2-3-1 formation

Team mentality, Normal, Focus passing, Mixed, Passing style, Mixed, Force counter-attacks, Off
Pressing style, High, Tackling style, Hard, Marking style, Zonal, Play offside trap, On

Defensive tactics for the 4-2-3-1 formation

Team mentality, Defensive, Focus passing, Mixed, Passing style, Mixed, Force counter-attacks, On
Pressing style, High, Tackling style, Hard, Marking style, Zonal, Play offside trap, Off

Final note

Even if you follow all these instructions, I guarantee an 80% result. Your team's training bonuses, morale, health condition, injuries during the match, weather conditions, and referee's decisions may change the outcome of the match.