City's 20 victories 'one of the greatest achievements' says manager Guardiola

''One of the greatest achievements in our careers'' -- that was the verdict of Manchester City manager Pep Guardiola after his side's 2-1 win over West Ham United on Saturday brought their 20th successive victory.

City won with goals from defenders Ruben Dias and John Stones -- and it was a result which extended their winning streak and lifted them 13 points clear in the English premier League.

It was also a victory which left their manager reaching for the superlatives -- Guardiola called the feat ''so difficult''.

Playing less than 72 hours after a Champions League match in Budapest, City produced one of its sloppiest displays in recent months but emerged with its winning run intact as Stones swept in the decisive goal in the 68th minute from Riyad Mahrez's pass.

Dias, Stones' partner in central defense, put City in front off a header from a deep left-footed cross by Kevin De Bruyne in the 30th only for Pep Guardiola's team to concede its first home goal in 2½ months when Michail Antonio equalized just before half time.