Chesterfield survived a second-half sending off to hold Coventry to a goalless draw at the Proact Stadium.The home side had Robbie Weir dismissed on the hour but Coventry could not take advantage as Marc McNulty wasted good chances.Coventry created early openings with McNulty forcing Tommy Lee to turn a 25-yard shot behind before Peter Vincenti headed a Jodi Jones cross over at the back post in the 22nd minute.But Coventry goalkeeper Lee Burge kept his side level by tipping over a 25-yard Jordan Flores free -kick in the 32nd minute and denied Kristian Dennis 10 minutes later.Lee turned a McNulty shot against the bar in the 52nd minute but his side were down to 10 men on the hour when Robbie Weir was shown a second yellow for a trip on Jones.McNulty missed a great chance when he went clear in the 72nd minute but shot wide and he should have scored in the 81st but he completely miscued his header from six yards.