
Reviewed for patch 7.3b

Favorable matchup
Reviewed for patch 7.3b
Draw a Bead makes Tristana's range grow with level, so her first levels are the shortest-ranged part of her game. Caitlyn pressures that phase with Piltover Peacemaker and turns the Rocket Jump landing into a risk with her traps.
Draw a Bead increases the range of her attacks, Explosive Charge and Buster Shot per level. In the first minutes, Piltover Peacemaker pierces the wave and punishes every step she takes toward a minion before she has that extra range.
Rocket Jump takes Tristana to a spot and slows around her when she lands. Yordle Snap Trap holds and exposes whoever steps on it: spread in front and to the sides, her comfortable landing falls next to one, and with Tristana trapped your Headshot reaches from twice the distance.
90 Caliber Net slows the target and the recoil knocks you back. If Tristana lands on you, use it to leave the slowed area and answer with the Headshot the net enables.
Trade in the early levels, when Tristana steps up to last-hit with her shortest range. If she has Rocket Jump and Explosive Charge ready, set traps before contesting the last-hit.
Tristana has to survive the early levels: last-hit from the side of the wave that Piltover Peacemaker can't pierce and don't jump into areas where Caitlyn may have left traps. Rapid Fire and the bomb win trades when she is the one walking up. Save Buster Shot to push her away if she chases you to your tower.

Favorable matchup
Reviewed for patch 7.3b
Rocket Jump resets on takedowns or on a fully charged Explosive Charge detonating on a champion. Draven punishes that dependency: he wins the basic-attack trade with Spinning Axe and uses Stand Aside to knock her aside and slow her before the fourth charge.
Explosive Charge is charged by Tristana's attacks and abilities and detonates early at four charges; only that full detonation on a champion gives her the jump back. Gaining distance before the fourth charge makes it harder for her to complete it, and without a full bomb there is no reset.
Spinning Axe adds damage to your next attack and bounces up for you to catch; with two axes in play, every basic attack Tristana trades during Rapid Fire meets a stronger answer. The 7.3a notes increase Spinning Axe, Blood Rush and Whirling Death.
Stand Aside throws your axes, knocking aside and slowing whoever it hits. If Tristana lands on you with Rocket Jump, pushing her away breaks her bomb-and-attack sequence and gives you time to leave the landing slow.
Trade when Tristana steps forward for a last-hit while you hold an axe. If she jumps on you, answer with Stand Aside before the bomb reaches its fourth charge.
On Tristana, don't place the bomb while Draven has Stand Aside and two axes: wait for him to spend the knock-aside. Rapid Fire helps you complete the four charges faster; pop it with the bomb, not after. Buster Shot knocks him away from where his axes are falling.

Execution matters
Reviewed for patch 7.3b
Rocket Jump is Tristana's way in and way out. Varus punishes the moment she spends it: Chain of Corruption roots the first champion hit and a charged Piercing Arrow wears her down from range. It works best with a support who follows up on the root.
Chain of Corruption roots the first champion and spreads to nearby ones. Thrown after Rocket Jump, it leaves Tristana without the tool she usually escapes with; thrown before, one jump is enough to dodge it.
Blighted Quiver applies Blight with your basic attacks and Piercing Arrow detonates it for damage based on maximum health; the arrow also gains range and damage the longer you charge it. That is how you chip Tristana without entering her bomb's radius.
Hail of Arrows slows and reduces healing in its area. Placed where Tristana lands after Rocket Jump, it keeps her within your support's reach for longer.
Fight after Tristana uses Rocket Jump or when your support locks her down. Without that, keep your distance and wear her down with Piercing Arrow.
Tristana wins this matchup if she keeps her jump: don't use it to engage while Varus has his ultimate, and push with Explosive Charge while he charges the arrow. If he roots you, Buster Shot knocks away whoever comes in on you. Look for the basic-attack trade while Chain of Corruption is on cooldown.