Grigor Dimitrov has progressed to the third round at Wimbledon with a straight-sets win over America's Steve Johnson.

The Bulgarian, who reached the semi-finals at last year's tournament, was pushed hard by the world number 52 in the first set, which remained on serve to force a tiebreak.

There was little to separate the two players, but the 11th seed eventually edged ahead after the duo had split the opening 16 points, wrapping it up 10-8.

Dimitrov appeared to have found his form in the second set as he quickly got two breaks on the board, racing to a 4-1 lead and comfortably holding serve for his next two games to extend his lead.

Johnson had regained his composure by the start of the third though, putting in solid performances on his service games to take a 5-4 lead, but Dimitrov fought hard to avoid being broken, eventually resulting in a second tiebreak.

The 11th seed picked up three of the four opening points to take control of the tiebreak, and allowed Johnson just one more before wrapping up the match.

Dimitrov will play France's Richard Gasquet, who is seeded 21st, in the next round.