Middlesbrough have now kept seven clean sheets this season.
Middlesbrough have been excellent so far this season, with Tony Pulis's side only losing one game in all competitions, leaving them second in the Championship and into the third round of the Carabao Cup.
Boro drew 0-0 with Swansea City in their most recent outing and the game could have easily been won by the Teesside team.
When speaking about Middlesbrough's chances of promotion this term, Randolph said: "Keeping clean sheets is a very important if you want success and if you want promotion. It sounds simple but concede the fewest goals in the league and the chances are you will go up.
"Most teams that go up get 20 odd clean sheets. For any kind of success in football you need to stop it going in."
The Republic of Ireland international kept his seventh clean sheet of the campaign and his fifth at the Riverside Stadium this term, making Randolph one of the best goalkeepers in the second tier.
Pulis's side have only conceded three goals in the Championship all season, two of which were on the opening day, and Middlesbrough fans will be hoping their excellent form continues to the end of the campaign, resulting in promotion to the Premier League.