Baggies' continued their recent run of form with a goalless draw against the league leaders at the Hawthorns, whilst the Italian raised concerns about January's fixture schedule
The Italian boss was left frustrated as his side dominated possession throughout but a determined display from Roy Hodgson’s men held the league leaders to a goalless draw at the Hawthorns.
“It’s impossible to win, we tried,” Mancini told reporters.
“It was difficult because West Brom played with everyone behind the ball, we couldn’t find a solution and we needed to score quickly in the second-half.”
The former Inter manager noted that whilst the Baggies decision to play with a number of men behind the ball caused City problems, his side should have taken advantage in the first half.
“Yes, it was the same at Stoke and today was the same," he continued.
“For this we need to improve in this situation, for when they get men behind the ball we need to improve. Maybe in the first-half we were to slow, but we had a chance and if we had scored the game would have changed.
“I said to the guys before the game if we don’t score in the first-half because I watched West Brom against Tottenham and they were very good. They lost the game 3-1 but they played very, very well.”
City have seen their five point lead at the top of the Premier League cut to just a goal difference advantage in recent weeks, and Mancini has raised concerns about his club's fixture schedule in comparison with other clubs challenging near the top of the table.
“I’m disappointed because we play January 1 then January 3 but Liverpool play December 29 and then January 3 against us," he said. "I think that this moment is not right, not good.
“I’m not happy, I don’t know why there is this situation. We know if we want to win the title and fight against United, because they are a strong team and to stay in the top four a long time we are strong enough to do this.”
The Eastlands outfit face a packed schedule throughout January, with the league game against Liverpool followed by the FA Cup third-round tie with Manchester United, as well a two-legged League Cup semi-final clash against Kenny Dalglish's side.
Despite the prospect of seven games in 25 days next month, Mancini is confident it will not affect his side's league hopes come the end of the season, even if they do temporarily slip into second.
“I think United will win their next game and for us it will be difficult as we play away at Sunderland and that will be difficult to play Liverpool after just 48 hours," he said.
“I’m confident that we can do a good job in the end. We play a lot of games in January and we could slip into second position but it is important to stay at the top at the end.”