Sessegnon has made an excellent early impression since his deadline day move from Sunderland.
The Benin international has played a major role in his side's climb up the Barclays Premier League table and was awarded the supporters' Player of the Month crown for October.
Sessegnon told Albion's official website: "There is a certain pressure to perform well because of the price tag, but it's a positive pressure because it shows the club think I'm worth it.
"I believe I can bring more to the club. There is still the settling period and I will show more as time goes by. It was quite difficult to make the change because I was at Sunderland for two years."