$\text{EGIK}$ is related to $\text{WUSQ}$ in the same way as $\text{DFHJ}$ is related to ______.

Let's examine the structural mapping relationship between $\text{EGIK}$ and $\text{WUSQ}$:
Consider positions of letters from the start and end of the English alphabet. The sum of positions of opposite pairs ($\text{A}\leftrightarrow \text{Z, B}\leftrightarrow \text{Y}$) is always $27$.

Let's see the sequence layout for $\text{EGIK}$:

* $\text{E}=5$ th from start. Opposite pair letter is $\text{V}(27-5=22)$. Moving $+1$ position ahead gives $\text{W}(23)$.
* $\text{G}=7$ th from start. Opposite pair letter is $\text{T}(27-7=20)$. Moving $+1$ position ahead gives $\text{U}(21)$.
* $\text{I}=9$ th from start. Opposite pair letter is $\text{R}(27-9=18)$. Moving $+1$ position ahead gives $\text{S}(19)$.
* $\text{K}=11$ th from start. Opposite pair letter is $\text{P}(27-11=16)$. Moving $+1$ position ahead gives $\text{Q}(17)$.

The rule is: Find the reverse alphabet letter, then shift it $+1$ position forward.

Applying this exact mapping pattern to $\text{DFHJ}$:

* $\text{D}=4$. Opposite is $\text{W}(23)$. Shifting $+1\to \text{X}$.
* $\text{F}=6$. Opposite is $\text{U}(21)$. Shifting $+1\to \text{V}$.
* $\text{H}=8$. Opposite is $\text{S}(19)$. Shifting $+1\to \text{T}$.
* $\text{J}=10$. Opposite is $\text{Q}(17)$. Shifting $+1\to \text{R}$.

This yields the string XVTR.