Pep Guardiola has insisted that his Manchester City side still have room for improvement, and must be more clinical if they are to maintain their winning ways.An early Riyad Mahrez strike was enough for the defending Premier League champions to see off Tottenham at Wembley on Monday night, but the manager was keen to emphasise the need for his team to be more efficient in front of goal.He said: “We played one of the most physical teams I’ve faced in my life because of Sissoko, Kane, Dier, Alderweireld, Sanchez and Dembele. It’s incredible physicality and this pitch was so complicated. We missed some goals and we let them run. Article continues below Editors’ Picks Man Utd ready to spend big on Sancho and Haaland in January Who is Marcus Thuram? Lilian’s son who is top of the Bundesliga with Borussia Monchengladbach Brazil, beware! Messi and Argentina out for revenge after Copa controversy Best player in MLS? Zlatan wasn’t even the best player in LA! “But we controlled quite good in terms of the difficulty to play on this pitch, especially in the first 15 to 20 minutes. In the second half we should have the game over and that is the problem we have.”In the big events, especially in the Champions League, we need to be more clinical in this situation because sooner or later we are not going to win.”He added: ”I still feel we have a lot to improve.”The win saw City move to the summit of the Premier League table on goal difference, with Guardiola’s side having conceded just three times in 10 league outings this season.Prior to Monday evening’s match there was much discussion surrounding the condition of the pitch at the national stadium, which had hosted an NFL fixture on Sunday afternoon, and Guardiola admitted that it did make for a difficult playing surface.He said: “We sometimes made mistakes because the pitch was complicated.”It’s a question for the Premier League and Tottenham. We were invited to come here for the fixture but hopefully they can solve that problem.”It was a good game in difficult conditions. To play a football game on that pitch is not easy, and that’s why there are many mistakes that normally don’t happen.”City take on Fulham in the Carabao Cup on Thursday, and will then face Southampton in the Premier League on Sunday, before hosting Jose Mourinho’s Manchester United for the first derby of the season the weekend after. Check out Goal’s Premier League 2019-20 fantasy football podcast for game tips, debate and rivalries.