West Indies had gone off to a great start at the World Cup 2019. A win over Pakistan prompted many to wonder if the side can be termed as the dark horses of the tournament. But things have changed for the side since then. Much like Bangladesh, who also had a fantastic start to the tournament, defeating South Africa in their opening contest. With the win, many started expecting that the side could produce a few more upsets in the tournament. But since then, things have gone downhill for the Lions.Bangladesh will have the psychological advantage when they face West Indies though both teams are sailing in the same boat as far as their World Cup campaign is concerned. Bangladesh beat West Indies as many as three times in tri-series that Ireland hosted ahead of the World Cup.Here are the five key player battles that could define West Indies vs BangladeshChris Gayle vs Mashrafe MortazaPlaying his final ODI tournament, Chris Gayle would feel he has a lot more to prove than how he has performed in the tournament so far. The left-handed batsman has not really been at his best and has just one fifty in three innings. Against Bangladesh, the batsman would look to target the skipper Mashrafe Mortaza from the first ball itself to put pressure on the opposition. Gayle has faced 158 deliveries from the seamer in ODIs over the years, in which he has scored 20 runs at a strike rate of 75.95. The bowler has dismissed him four times and he would be eager to make it fifth.Mustafizur Rahman vs Shai HopeShai Hope holds a tremendous record against Bangladesh’ best bowler Mustafizur Rahman. The left-armer has bowled 147 deliveries to the batsman over the years, in which the batsman has slammed 178 runs at a strike rate of 121.09. The bowler has never been ever to dismiss the batsman. Rahman would be eager to improve his record against the Windies’ middle-order batsman.Nicholas Pooran vs Shakib al HasanNicholas Pooran has never faced Shakib al Hasan in the ODIs format. But despite his ability to hit big shots, his struggles against spin bowling have been exposed in the tournament. Shakib al Hasan has been able to get wickets and stop the run rate in the middle overs. He would enjoy the contest agains the West Indies. The allrounder has dismissed the left-handed batsamn once in the T20Is.Oshane Thomas vs Tamim IqbalOshane Thomas has emerged as the revelation in the tournament for the West Indies bowling unit. The right-armer has been fantastic throughout the series, taking wickets with the new balls and then contributing in the death overs as well. Thomas would look to go on against Tamim Iqbal, who has given a good start to Bangladesh, but has failed to capitalise on it. The left-handed batsman would hope to tackle the threat and set a platform for Mushfiqur Rahim and Shakib to build the innings on.Jason Holder vs Mushfiqur RahimMushfiqur Rahim has never enjoyed batting against Jason Holder in any format. In Tests, the batsman has faced 23 deliveries from the Windies captain and has been dismissed twice. In the ODIs, Rahim has faced 74 balls from the seamer and has scored just 85 runs and has been dismissed once. This is a contest that could define Bangladesh’s innings.