Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

T. Rowe Price All-Cap Opportunities Fund (PRWAX Quick QuotePRWAX - Free Report) has a 0.79% expense ratio and 0.64% management fee. PRWAX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. With yearly returns of 14.86% over the last five years, this fund clearly wins.

JPMorgan US Equity Fund R5 (JUSRX Quick QuoteJUSRX - Free Report) is a stand out amongst its peers. JUSRX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. With five-year annualized performance of 12.48%, expense ratio of 0.54% and management fee of 0.4%, this diversified fund is an attractive buy with a strong history of performance.

Fidelity Select Semiconductors (FSELX Quick QuoteFSELX - Free Report) . Expense ratio: 0.69%. Management fee: 0.53%. Five year annual return: 27.18%. With a much more diversified approach, FSELX--part of the Sector - Tech mutual fund category--gives investors a way to own a stake in the notoriously risky tech sector.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.