How do I select this non-visible link lacking id with Selenium WebDriver?

I'm trying to select this link, 'User Requested'. It appears when the mouse hovers over the menu.

It has this HTML

<ul class="k-widget k-reset k-header k-menu k-menu-horizontal" id="menu" data-role="menu" tabindex="0" role="menubar" aria-activedescendant="menu_mn_active">
...
<li class="k-item js-first-level k-state-default k-state-border-down" role="menuitem" style="z-index: 100;">
  <span class="k-link js-first-level k-state-active k-state-border-down" target="">Reports/Analytics<span class="k-icon k-i-arrow-s"></span></span>
  <div class="k-animation-container" style="width: 152px; height: 145px; margin-left: -2px; padding-left: 2px; padding-right: 2px; padding-bottom: 4px; overflow: visible; display: block; position: absolute; z-index: 10002; top: 27px; left: -2.703125px;">
    <ul class="k-group k-menu-group k-popup k-reset k-state-border-up" role="menu" data-role="popup"
    style="max-height: 578px; overflow: auto; display: block; font-size: 12px; font-family: &#39;Open Sans&#39;, sans-serif; font-stretch: normal; font-style: normal; font-weight: normal; line-height: normal; position: absolute; -webkit-transform: translateY(0px);">
      <li class="k-item js-second-level k-state-default k-first" role="menuitem">
        <a class="k-link js-second-level" href="..." target="">Reports / Analytics</a>
      </li>
      <li class="k-item js-second-level k-state-default" role="menuitem">
        <a class="k-link js-second-level" href="..." target="">User Requested</a>
      </li>

The XPath

//*[@id="menu"]/li[10]/div/ul/li[2]/a

The code

  echo "Switching to mainFrame\n";
  $driver->switchTo()->frame("mainFrame");
  echo "Finding link Reports/Analytics\n";
  //$input = $driver->findElement(WebDriverBy::partialLinkText('Reports/Analytics')); #didn't work
  $input = $driver->findElement(WebDriverBy::xpath('//*[@id="menu"]/li[10]/span'));
  $input->click();
  echo "Finding link User Requested\n";
  // $input = $driver->findElement(WebDriverBy::partialLinkText('User Requested')); # didn't work
  $input = $driver->findElement(WebDriverBy::xpath('//*[@id="menu"]/li[10]/div/ul/li[2]/a'));
  $input->click();

The error

Switching to mainFrame
Finding link Reports/Analytics
Finding link User Requested
PHP Fatal error:  Uncaught exception 'NoSuchElementException' with message 'no such element

It seems no matter what I try, it won't work. There is no id for the link.

---

I managed to get a link clicked, but it selects the wrong link! I'm using Chrome to right click on the elements to get the CSS Path and XPath. (Some JavaScript sets an id menu_mn_active when a menu is selected.) The element shows the text is correct, but it is going to the wrong page.

  echo "Finding link User Requested\n";
  // $input = $driver->findElement(WebDriverBy::partialLinkText('User Requested'));
  // $input = $driver->findElement(WebDriverBy::cssSelector('#menu_mn_active > div > ul > li:nth-child(2) > a'));
  // $input = $driver->findElement(WebDriverBy::xpath('//*[@id="menu"]/li[10]/div/ul/li[2]/a'));  
  $input = $driver->findElement(WebDriverBy::xpath('//*[@id="menu_mn_active"]/div/ul/li[2]/a'));
  echo("Link text: ".$input->getText()."\n");  
  $input->click();
  echo "Finding link Export Employees To Bamboo\n";

Output

Finding link User Requested
Link text: User Requested
Finding link Export Employees To Bamboo
PHP Fatal error:  Uncaught exception 'NoSuchElementException' 

I also frequently get this error when trying to click the item in the slide down menu:

PHP Fatal error:  Uncaught exception 'ElementNotVisibleException' with message 'element not visible

It was because the size of the browser window that the Chrome driver pops up. The window is an odd shape that is narrower than normal and the element I was trying to click was ever so slightly out of the view port by a few pixels, even though it was clearly visible to me. When I manually adjusted the size of the window everything worked perfectly! I added this line near the beginning of the session and it works:

  $driver->manage()->window()->maximize();

Also, it won't work if my mouse is hovering over the window! And I have to add a sleep() to wait for the menu to slide out.