England v West Indies: Alastair Cook says 'jury still out' on pink ball

The "jury is still out" on the pink ball being used in the day-night Test against West Indies, says England's opening batsman Alastair Cook.

The former captain scored 153 not out on day one at Edgbaston, as England closed on 348-3.

The England and Wales Cricket Board believes the Dukes ball is the closest in form to the traditional red one used in first-class and Test cricket.

"We'll know more two or three years down the line," said Cook.

"We'll then be able to see how it reacts in all kinds of situations, but I thought it was a good ball."

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21,649 spectators attended the first day of the inaugral day-night Test in the UK

Cook scored 23 boundaries and batted out the full 90 overs of the opening day of the inaugural day-night Test in the UK.

"I can't see this not being a success in other parts of the world, but whether we need to do it in England is a different matter," he said.

"The trouble is that it's not dark until the last hour in England. In other parts of the world you get a session and a half in the dark."

The match began at 14:00 BST, with 'lunch' taken at 16:00, 'tea' at 18:40 and play finishing at 21:30.

"I was yawning at nine o'clock because that was about my bed time," said Cook.

"You're programmed to start at 11 with a red ball - the change can take a little bit of time."

The Essex batsman shared a 248-run partnership with captain Joe Root, the highest for the third wicket in a Test at Edgbaston.

Cook described Root - who made 136 - as a "genius," adding: "It's incredible how he manages to score like he does. If he's not the best English player I've played with then he's right up there.

"The way he moves, his rhythm - it's a lesson to us all."

West Indies bowling coach Roddy Estwick said the tourists were "disappointed in the dressing room", after the bowlers conceded 53 boundaries over the course of the day.