England skipper Alastair Cook was left to rue a series of missed chances in the field as England went down to India by an innings and 36 runs in Mumbai leaving sealing the series for the hosts.
The tourists have not been very sharp in the field and their mistakes cost them dearly in Mumbai where they dropped Virat Kohli twice on his way to a double ton which set up the emphatic win.
To make matters worse at the time of the drop England looked set to establish a first innings lead but would ultimately see India reach 631 all out, 231 runs ahead.
England missed out on stumping Murali Vijay when he was on 45 and Joe Root dropped Jayant Yadav on 8 with both batsmen going on to record hundreds.
Cook told Star Sports: "I keep going back to the chances we missed.
"That's why we lost this game.
"Yes, we would have liked another spinner. But with the side we had, we had opportunities to bowl India out for 400 and we just didn't take them.
"Obviously Virat played an extraordinary innings, but we had a chance to get rid of him on 60-odd. Yadav got a 100 and we had a couple of chances to get rid of him.
"And those are the things the game is changing on. This team, at the moment, we're not taking those chances. It's those opportunities that have cost us."
Cook admitted that England had fluffed the team selection opting to pick an extra seamer that proved surplus to requirements and using Joe Root as a makeshift spin option.
He said: "That was a mistake.
"It's kind of the problem when you don't have any games between Test Matches. We really wanted to see what four seamers looked like, because they are the bowlers so far on this tour who have given us the most control and our two best spinners have been Mo and Rash.
"Maybe if we'd bowled first we'd have more control with the four seamers. But clearly when you bat first, you didn't need that extra seamer.
"Whether it would have changed the game… we were in this game with the balance of that side. We had an opportunity when they were 307 for 6 to restrict India's lead.
"Historically, 180 is a good score here in the third innings and it's very hard to score much in the fourth innings. So we would have been in the game.
"But would have, could have isn't really good enough and that's the bottom line: we haven't been good enough to get over the line."
Cook was full of praise for his opposite number Kohli who stood tall and carried India to victory so well.
The captain said: "He's in incredible form. He's having one of those series you dream of as a player and a captain. You lead from the front and you score a hell of a lot of runs and that's a huge amount of credit to him.
"He's clearly one of the great batsmen of our generation. And certainly in these conditions, he's very hard to bowl at when he's in this form."