Yes they can
Spartacus was a real person who commanded in the Third Servile War - 73BC - 71BC (also called The Gladiator War or The War of Spartacus)
This war went on for almost 3 years with the rebellious slaves holding their own against the various forces of Rome, from Local Militia up to full fledged consular Legions.
The unorthodox tactics employed by Spartacus and the slaves caught a lot of the Roman military forces off guard.
In their first battle against Roman forces following their escape - The Battle of Mount Vesuvius, they fortified themselves on the slopes of the volcano, and then when the Romans lay siege to their camp, they rappelled (using ropes made from vines) down the mountain and flanked the Militia sent to "deal" with them, annihilating them.
A second Militia was then defeated soon after.
Now defeating a militia is not the same as defeating the might of the Roman Legions... But...
in 72BC 2 Consular Legions were then dispatched commanded by Gellius and Lentulus. First blood when to the legions with Gellius' destroying a slave army (not commanded by Spartacus) near Mount Garganus.
Spartacus, with the majority of the slave army then defeated both Legions in quick succession.
In 73BC Crassus (Yes that Crassus) was given command of the Legions tasked with bringing the rebellion to a stop.
It started badly when 2 of his Legions were routed following disobedience of one of Crassus' subordinates. Crassus decimated the legions for this.
However the tide soon turned and eventually Spartacus and the slaves were defeated. Extra legions were sent under the command of Pompey (Yes that Pompey) though they only rounded up routed slaves.
Therefore gladiators have broken Roman formations a number of times in real life.