It was a memorable night in Cedar Rapids for two of the Twins' most promising young hitting prospects Tuesday.

On his 19th birthday, last year's No. 1 overall pick Royce Lewis hit his first professional grand slam. Lewis blasted a 2-0 pitch over the left field fence, turning a 3-2 Cedar Rapids lead into a 7-2 advantage.

Not to be outdone, 20-year-old teammate Alex Kirilloff hit a grand slam of his own later in the game, part of a 14-3 rout of Beloit.

Lewis is hitting .294 with four home runs, while Kirilloff is tearing up the league with a .330 average and 11 home runs.

Videos of both home runs are available on the blog, and the visual evidence helps.

Lewis is quite young for Class A, but his home run swing is very easy and smooth.

Kirilloff, a lefthanded hitter, hit his slam to the opposite field off a lefthanded pitcher — both impressive feats.

Read Michael Rand's blog at startribune.com/randball. michael.rand@startribune.com.