While he may not have the efficiency that comes with years of learning and mastering a craft yet, David Robertson likely has some time to figure out how to close out games better for the New York Yankees.

After some nervy moments, Robertson and the Yankees continue their series against the co-leaders of their division - the Tampa Bay Rays - on Wednesday night.

The closer's job in the Bronx had been taken for granted for nearly a generation with Mariano Rivera, but Robertson inherited the role when baseball's all-time saves leader went down with a season-ending knee injury last Thursday in Kansas City.

The hard-throwing right-hander had his first opportunity in the future Hall of Famer's cleats and made things interesting by loading the bases with two out Tuesday, but Robertson struck out Carlos Pena to end the game and preserve a 5-3 win for New York (16-13).

"Tonight I was thinking, 'Geez, better not blow your first one,''' Robertson said. ''Better not blow your first opportunity or Mo might come in here and smack me around.'

"I think Mo would've thrown 12 pitches and broke a bat and we would have been out of here 20 minutes ago."

Robertson threw 25 pitches, three off his season high, and has been used on consecutive days three times this season. In those games, he has recorded three scoreless one-inning outings while fanning five, but also has shown an ability to make out pitches - Robertson has thrown less than 20 pitches in each appearance.

"The important thing is that David doesn't try to be Mo, that David is just David," manager Joe Girardi told the team's official website. "You want to get on a good little run. But he wants to get on a little run because he wants to win for our club."

As Robertson tries to hold down a legend's spot, rookie David Phelps (0-1, 3.74 ERA) appears to be keeping a place warm for another from Yankees lore in what likely will be his second and final turn through the rotation. The right-hander likely will be bumped since Andy Pettitte is slated to make his season debut Sunday after working an extended spring training.

Phelps made his first major league start the day Rivera tore his ACL shagging flies during batting practice, giving up two runs and six hits in four innings while striking out five in New York's 4-3 loss at Kansas City. He has been solid in his two long relief outings at Yankee Stadium, yielding only a solo homer with three walks and six strikeouts in 8 1-3 innings.

Tampa Bay (19-11) remained tied with Baltimore atop the AL East with its third straight loss - one off its season high from April 12-15. The Rays went 0 for 7 with runners in scoring position - capped by Pena's game-ending strikeout - and are 2 for 20 during their skid.

"We had good opportunities, it just did not work out,'' manager Joe Maddon said. ''We just haven't been able to do it the past couple of games.''

Jeff Niemann (2-3, 4.05) will try to be Tampa Bay's streak stopper as he seeks consecutive wins for the first time this season. The right-hander is 0-3 on the road, but the Rays have provided just four runs for Niemann in those outings.

Niemann matched a season high Thursday with 5 2-3 innings, giving up three runs and seven hits in a 4-3 victory over Seattle.

Niemann, though, does seem to like pitching at Yankee Stadium, where he is 2-0 with a 3.00 ERA in four lifetime starts. He limited the Yankees to one run and six hits in 7 1-3 innings there July 7 in his only start against them in 2011.