Machamp is one of GSC's deadliest attacking threats, mostly thanks to its 358 Attack-backed STAB Cross Chop. Cross Chop is not only an incredibly useful Fighting-type STAB move, which is super effective or at least neutral against most of GSC's big players, but it also has a 20% critical hit rate after factoring accuracy, adding to its already devastating strength. Curse is what really allows this Machamp set to shine, as after a Curse boost, Cross Chop is able to OHKO even the vaunted Skarmory with a critical hit. As a pure physical attacker, being able to kill Skarmory, much less in one hit, is an impressive feat indeed. Furthermore, even though it's a Curse sweeper, Charm Umbreon and Growl Miltank can't just switch in to stall it thanks to its super effective Fighting-type STAB. A few teams fail to carry a Fighting resist; for these teams, Skarmory is often all they have to attempt to wall Machamp, and Skarmory will die if it gets hit by a boosted critical hit Cross Chop, forcing the team to crumble shortly thereafter.
Of course, there are several common Fighting-type resisting Pokemon that can step in to serve as more capable Machamp walls. Even then, though, Machamp gets a slew of coverage moves to handle them. Rock Slide 2HKOs the ever-present Zapdos after a Curse boost, whereas the choice of Hidden Power is able to 2HKO other defensive threats. An unboosted Hidden Power Bug 2HKOs the common Exeggutor. An unboosted Hidden Power Ghost on the other hand is able to 2HKO the Ghost-types on average while still retaining the ability to 3HKO Exeggutor. Hidden Power Bug is usually preferred because Exeggutor directly forces Machamp to switch out with its STAB Psychic whereas Ghost-types still take a lot of damage from Curse-boosted Rock Slides and can't threaten direct damage to Machamp to force it out easily. Regardless of which Hidden Power is chosen, they both also give Machamp some recourse against its number one check: Starmie. Starmie without Reflect are 2HKOed by Hidden Power after a Curse boost, and Reflect variants are 2HKOed after three Curse boosts, which are easily obtainable without taking too much damage from Surf if Machamp Curses on the turns that Starmie switches in and uses Reflect. Thanks to the combination of Curse and Hidden Power, in addition to the fact that Starmie's Surf only 4HKOes Machamp, Starmie needs to run Psychic to consistently scare Machamp into switching out with the threat of the 2HKO, and even then Machamp can still kill a weakened Starmie (62-73% health) with a Curse-boosted Hidden Power while being able to tank a single STAB Psychic with plenty of health to spare. Even considering all of this, though, Machamp could simply rely on its team to clear out Starmie for it and instead use Fire Blast in the last slot, which handily 3HKOes Exeggutor and allows Machamp to easily KO Skarmory without burning through precious Cross Chop PP attempting to score the critical hit.
Machamp's ability to tank hits, especially STAB Water-type attacks, constitutes one of its main selling points over the similar Swords Dance Marowak (the other being the raw wallbreaking potential of a boosted critical hit Cross Chop). However, while Machamp has an easier time setting up because of its ability to take hits, it shouldn't be switching into attacks very often, as if it does, its lack of resistances or a recovery move means that it will simply be worn down without being able to use that extra bulk to set up. Because of this, it needs to be played similarly to Marowak in that it needs to be switched in judiciously on predicted non-attacking turns on the opponent's part, preferably on predicted switches to Snorlax to nab a free turn to set up Curses or predict switches to Exeggutor as the opponent will undoubtedly switch out to avoid taking the possible STAB Cross Chop. However, while Machamp isn't immediately forced out by anything with an attacking move and a modicum of Defense the way Marowak is, it does rely on a much less accurate, less reliable, and more PP-starved STAB move than Marowak does. Indeed, as often as Cross Chop can win games by breaking key walls with timely critical hits, it can also disappoint with untimely misses, forcing Machamp to become worn down without accomplishing anything on the offensive, even if played perfectly.
Curse sweeping Machamp, much like Swords Dance Marowak, loves plenty of support to help it get in position to break walls. Paralysis is first and foremost the biggest assistance to this Machamp. A paralyzed Skarmory is unable to use Curse after switching in on Machamp's Curse, rendering it unable to stall out Machamp's Cross Chop PP as it attempts to score a critical hit. Furthermore, paralyzed Umbreon cannot switch in on a turn that Machamp uses Curse to neutralize Machamp by setting its Attack stage to -1; Machamp can't afford to waste Cross Chops on turns when its Attack stage is so low, as even against Umbreon, which takes super effective damage, a -1 Cross Chop fails to 2HKO without a critical hit. In general, paralysis is great even against the foes Machamp is supposed to set up against and beat; it prevents Machamp from being worn down every turn that it chooses to attack, and can transform the possible Cross Chop miss from a potential sweep-ender to a minor inconvenience. Some of the better paralysis-spreading partners for Machamp include Stun Spore Exeggutor, Thunder Wave Starmie, Thunder Wave Zapdos, and Body Slam Snorlax.
Other support that is appreciated by Machamp includes Pokemon that can bait its counters to switch into Explosions. Cloyster is probably the best at this, as it can bait Starmie in to spin away its Spikes, only to subsequently Explode on it and free up Machamp to rampage. Exeggutor and Steelix often end up catching foes such as Zapdos and Suicune that can otherwise wear Machamp down with their STAB special attacks. Machamp usually beats these foes if it Curses on the turn that they switch in, but it takes a lot of damage in the process, so being rid of the likes of Zapdos and Suicune beforehand is a great help to Machamp's sweeping efforts. Further support includes Pursuit users. Tyranitar, Umbreon, and Houndoom are all adept at catching Exeggutor, which otherwise causes Machamp problems by forcing it out with STAB Psychic. They are also all good at forcing Ghost-types to take residual damage to put them in +1 Rock Slide 2HKO range if Machamp opts for Hidden Power Bug over Hidden Power Ghost. Furthermore, Tyranitar can severely weaken Zapdos with Pursuits on the switch out, whereas Umbreon can use the combination of Toxic and Pursuit to force Starmie into +1 Hidden Power OHKO range before it can switch in to combat Machamp. Finally, Rapid Spin support from Starmie can be a great help to give Machamp more leeway to predict opportunities to switch in. However, it's not absolutely necessary for Machamp, as it can often restore the health lost to Spikes with Leftovers as it stays in to set up, whereas other heavy-hitters such as Marowak and Rhydon need Rapid Spin support much more because they are usually limited to using one attack before being forced to switch out.
While this Machamp is well-tailored to take on its most common checks, there are still a few things it will struggle mightily to get past. Nidoking resists everything it has except for the weak Hidden Power Ghost, although its offensive nature means that it lacks a recovery move itself, and its moderate attacking stats mean that it won't be able to do much damage to Machamp in return, thereby allowing Machamp to set up fairly safely against Nidoking unless it has yet to use Lovely Kiss. Heracross poses a bigger problem to Machamp; it resists Cross Chop and can either Curse up alongside Machamp or wear it down with Seismic Toss. A +2 Rock Slide will 3HKO an unboosted Heracross, though, as will an unboosted Fire Blast should Machamp be using it, so Seismic Toss will not KO Machamp in time if it Curses on the switch unless Heracross gets lucky and consistently hits Rest and Seismic Toss with Sleep Talk at critical moments. Muk is probably the toughest thing for Machamp to deal with, as it resists Cross Chop, Curses up alongside Machamp, and can dish out heavy damage in return with Sludge Bomb. However, Muk is usually on a suicide mission and often uses Explosion to take itself out of commission, thereby effectively dealing with itself to allow Machamp an opportunity to sweep. These threats are far less common and effective as Machamp checks than the likes of Zapdos and Exeggutor, and as a result, using moves such as Earthquake and Fire Blast to deal with these threats is rare and generally not worth the trouble.