If there is one thing to say about Diglett, it's that it follows in its evolution Dugtrio's footsteps. They both have pathetic defenses and an average Attack stat, but what makes them unique is Arena Trap. In Little Cup, Diglett is a threat that must certainly be watched out for. While it seems that Diglett lacks enough Attack to function as a revenge killer, don't let this fool you, as many Pokemon in Little Cup are not too defensively oriented. With powerful moves and absolutely amazing Speed, Diglett is definitely a unique Little Cup Pokemon.
While Diglett is tailored to be a successful revenge killer, it functions as a very effective lead as well. The qualities that make it a successful lead include Arena Trap (which gives it solid anti-lead capabilities), high Attack and Speed stats, powerful priority, and access to Stealth Rock. Arena Trap is particularly important, since it it stops your opponent from switching out of a bad lead match up.
Diglett is one of the most successful Stealth Rock leads in Little Cup, as its extraordinary Speed allows it to outpace nearly every lead outside of Voltorb, meaning it will almost always move first. Earthquake is Diglett's most powerful move and cannot be ignored on any set. The choice between Shadow Claw and Sucker Punch depends on your personal preference, as they both have their positive and negative points. Shadow Claw allows Diglett to deal with Substituting Ghost-types, such as Drifloon, all of the time, which Sucker Punch can't accomplish. Sucker Punch, however, is the strongest priority move in the game (tying with ExtremeSpeed), and it is necessary to pick off Focus Sashes and priority-using leads. Finally, Protect is a must in Diglett's fourth move slot. Lacking Protect will allow Fake Out leads like Meowth and Buneary to render Diglett's Focus Sash useless and defeat it after that with their STAB Returns.Team Options & Additional Comments >>>
When equipped with a Life Orb or Focus Sash, as opposed to Choice Band, Diglett is able to freely use all four of its deadly moves. This set can really threaten the Little Cup metagame, as Diglett is one of the best revenge killers available.
The main point that makes this set different from the others is the presence of Substitute. In the process of revenge killing, Diglett may sometimes manage to switch into a Choiced Electric-type move, so it can set up a Substitute for free and finish off the foe with the appropriate attack. Earthquake is Diglett's main STAB attack. Sucker Punch provides Diglett with a useful priority move that helps against Choice Scarfed foes that can OHKO Diglett. Note that if Diglett does have a Substitute up, and your opponent is faster than it and breaks Diglett's Substitute, you can almost be sure that it is Scarfed, a fact that can be exploited by the rest of your team. Next, Hidden Power Ice is necessary to combat Gligar; without it, Gligar will wall this set all day long, while able to launch Earthquakes that will OHKO Diglett instantly. Hidden Power Ice is also Diglett's best option (besides Aerial Ace) to hit Grass-types that resist Earthquake for super effective damage. If Substitute is not preferable, you may choose to use a Focus Sash as well. In this case, it is recommended that you use either Rock Slide or Shadow Claw for a broader range of attacking options.Team Options & Additional Comments >>>
Diglett is a prevalent and terrorizing force in Little Cup, as it can easily trap and dispatch of its opponents thanks to Arena Trap. Add a series of particularly powerful moves to the mix, and Diglett becomes one of the best revenge killers in Little Cup, able to OHKO a variety of Pokemon.
Earthquake is Diglett's most powerful attack. Even if it seems to lack the Attack stat to do much damage, a STAB Earthquake can actually strip off large amounts of health from anything that is not resistant or immune to it. Hidden Power Ice may seem odd on Diglett at first glance, but in fact, it is Diglett's only way to deal massive damage to Gligar, while also hitting other Grass-types that resist Earthquake for super effective damage. Sucker Punch is Diglett's best bet against Ghost-types, particularly Choiced ones like Gastly. Even if Diglett is already fast, Sucker Punch's priority can help it out against faster opponents and other users of priority attacks. The last moveslot has two interesting options. Shadow Claw is mainly used to keep Ghost-types from setting up against Sucker Punch, such as Drifloon and Gastly. On the other hand, Rock Slide can also be used to provide near perfect coverage alongside Earthquake (only resisted by Bronzor and Baltoy) and hit most Flying-types, such as Mantyke and Taillow, for super effective damage.Team Options & Additional Comments >>>
Diglett doesn't have too many other useful options to use, as its movepool is rather limited. Pursuit can be used to trap Levitating Ghost- or Psychic-types that try to avoid Diglett's Arena Trap, and Aerial Ace can be used to hit Grass-types.
Checks and Counters
Diglett can be easily dealt with by having a physically defensive Pokemon, particularly Bronzor, Gligar, or Phanpy. The aforementioned Pokemon are capable of taking several hits from Diglett and return with their STAB attacks. Bronzor is Diglett's best counter, since it has Levitate and takes pathetic damage from any of its other moves.
Substitute-using Ghost-types, like Drifloon and Gastly, are also solid counters if Diglett lacks Shadow Claw. They can set up a Substitute as Diglett attempts to Sucker Punch them, allowing them to finish off Diglett with Shadow Ball safely.
Grass-types like Paras and Snover can take Diglett's Earthquake and OHKO it back with their STAB Grass-type (or Ice-type in Snover's case) moves. Hidden Power Ice can hurt them, but they are not wounded too badly. However, Paras and Snover should watch out for Rock Slide.
Pokemon that are faster than Diglett spell trouble, because even moderately powered attacks can finish it off instantly. Examples of these are Choice Scarf Machop, Staryu, and Mankey, assuming Diglett is not Scarfed as well.