Koren started all three play-off games as Albion beat Wolves in the two-legged semi-final but lost 1–0 to Derby County in the Wembley final.

In July 2007 Koren suffered a freak accident in training when a ball hit him in the eye, causing internal bleeding and temporary loss of vision.

[4][5] The injury meant that he missed the start of the 2007–08 season, but he returned to the side at the end of August as a substitute in a League Cup game against Peterborough.

[10] Koren continued to be a regular starter during the 2009–10 season under new manager Roberto Di Matteo, making 34 league appearances and scoring 5 goals, including a brace in a 3–0 home win against Leicester City in April as West Brom sealed an immediate return to the top flight.

[18] On 29 November 2011, against Southampton at St Mary's Stadium, a flowing move down the left ended with Tom Cairney pulling the ball back to Koren, whose shot deflected off Matty Fryatt and brought a stunning save out of Kelvin Davis.

[19] On 3 December 2011, against Leicester City at the KC Stadium, the ball was rolled nicely into the path of Koren and he struck a beautiful shot past Schmeichel from 20 yards.

[20] On 7 December 2011, against Birmingham City at the KC Stadium, Cameron Stewart got to the byeline down the right before firing in a vicious cross that was only cleared as far as the penalty spot where Koren readjusted his body to volley into the net.

[23] On 15 September 2012, against Millwall at the KC Stadium, Koren picked up possession on the edge of the centre circle, advanced unchallenged before unleashing a powerful drive from 25 yards which flew past Taylor and into the net.

[27] Koren made his debut for Slovenia in an April 2003 European Championship qualification match against Cyprus and earned a total of 61 caps, scoring 5 goals.